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Ecstasy (drug)
MDMA (3,4-methylenedioxymethamphetamine), most commonly known today by the street name ecstasy, is a synthetic entactogen of the phenethylamine family whose primary effect is to stimulate the secretion of large amounts of serotonin as well as dopamine and noradrenaline in the brain, causing a general sense of openness, empathy, energy, euphoria, and well-being. Tactile sensations are enhanced for some users, making general physical contact with others more pleasurable, but contrary to popular mythology, it generally does not have aphrodisiac effects. Its ability to facilitate self-examination with reduced fear has proven useful in some therapeutic settings, leading to its 2001 approval by the United States FDA for testing in patients with post-traumatic stress disorder.
Acute dehydration is a risk among users who are highly physically active and forget to drink water, as the drug may mask one's normal sense of exhaustion and thirst. Also the opposite, "water intoxication" resulting in acute hyponatremia has been reported. By far the biggest danger comes from the fact that other, more dangerous chemicals (such as PMA, DXM or methamphetamine) are either added to ecstasy tablets, or more often simply sold as ecstasy. Long-term effects in humans are largely unknown and the subject of much controversy —particularly with regard to the risks of severe long-term depression as a result of a reduction in the natural production of serotonin.
MDMA is also known by many other street names, including Adam, Beans, Candy, Disco Biscuits, E, Eccies, Googs, Jack and Jills, MaDMAn, M&Ms, Mollies, Pills, Rolls, Scoobies, Smarties, Tabs, Vitamin E, Vitamin X, X, XTC, Yaotou (in East Asia) and Yokes.
History
A patent for MDMA was originally filed on Christmas eve 1912 by the German pharmaceutical company Merck, and granted two years later (to the day.) At the time, MDMA was not known to be a drug in its own right; rather, it was patented as an intermediate chemical used in the synthesis of a styptic (a drug intended to control bleeding from wounds.) Over half a century would pass before the first known ingestion of MDMA by humans.
Contrary to many rumours, the drug was never used as an appetite suppressant or as a stimulant for armed forces during wartime. (This was in fact methamphetamine.) The U.S. Army did, however, do lethal dose studies of it and several other compounds in the mid-1950's. It was given the name EA-1475, with the EA standing for Edgewood Arsenal. The results of these studies were not declassified until 1969. MDMA was first brought to public attention through Dr. Alexander Shulgin in the 1960s who recommended it for use in certain therapy sessions, naming the drug 'window' (he discovered it while searching for compounds that might have a similar psychoactive effect as other compounds contained in nutmeg). It was widely used therapeutically by US psychotherapists (especially on the West Coast) because of its empathogenic effects until its criminalization in the late 1980s. The drug was hailed as a miracle by therapists and counselors who claimed couples could have six months worth
of progress in one use of the drug, and soldiers returning from the Vietnam war could overcome their PTSD sometimes more effectively than talk or group therapy. A small number of therapists continue to use it in their practices today. (See below for 2001 FDA approval and DEA licensing for use in patients with post-traumatic stress disorder.)
Until 1985, MDMA was not illegal in the United States. Recreationally, it first came into prominence in certain trendy yuppie bars in the Dallas area, then in gay dance clubs. From there, use spread to rave clubs, and then to mainstream society. During the 1990s, along with the growing popularity of the rave subculture, MDMA use became increasingly popular among young adults in universities and later in high schools. It rapidly became one of the four most widely used illegal drugs in the US, along with cocaine, heroin and marijuana.
Chemistry
The chemical structure of MDMA is similar to those of mescaline and methamphetamine, but the phenyl ring is substituted with a methylenedioxy group in position 3,4.
It is a member of the phenethylamine family, a group of substances typically having pronounced biological activity.
MDMA is synthesized from MDP2P through a chemical reaction known as reductive amination. MDMA has a chiral center at the alpha carbon (next to the methylamino group).
Pharmacokinetics
MDMA has complex nonlinear pharmacokinetics, due MDMA's ability to inhibit CYP2D6. It is metabolised via N-demethylation to several active metabolites including MDA, although the conversion rate in humans is low. The metabolism is primarily by the cytochrome P450 enzymes CYP2D6 (in humans, but CYP2D1 in mice), and CYP3A4 . Large increases in blood and brain concentrations are mostly due to autoinhibition of CYP2D6 metabolism--if the user takes consecutive doses of the drug, disproportionately high plasma concentrations can result.
A significant quantity is excreted unchanged in the urine, especially when the drug is taken at higher doses.
Ecstasy as a recreational drug
The primary effects of MDMA include feelings of openness, euphoria, empathy, love, and heightened self-awareness. Its initial adoption by the dance club sub-culture is probably due to the enhancement of the overall social and musical experience. Taking MDMA or Ecstasy is commonly referred to as rolling, popping, dropping, pilling, flipping, getting off-tap, "eating skittles", dosing, thizzin.
MDMA use has increased markedly since the late 1980s and spread beyond its original sub-cultures to mainstream use. Prices have also fallen since its introduction, with an evening's drug use often costing less than an equivalent evening drinking alcohol, although street price can vary between as little as $5 to as much as $40 per tablet. This depends on the drug being bought beforehand or on the place of usage (which drastically increases price). In countries in which distribution is more extensive, such as in the Netherlands, prices can sometimes be as low as $1 per tablet. In Britain, a usual price is around £2.50 for a pill (although recent media reports as of September 2005 show the price dropping as low as 50p in many parts of the country), and £20 for a half gram of pure MDMA powder, although like any illegal substance the price varies wildly depending on how many hands it has passed through. In the U.S. the prices varies anywhere from 10$ a pill to 30$. In countries where distribution is more difficult prices are accordingly higher; for example in New Zealand prices start at around $30 NZD ($15 US) and can get as high as NZ $80.
Supply and administration
MDMA is usually ingested in pill form. Pills come in a variety of "brands", usually identified by the icons stamped on the pills. The brands never consistently designate the actual active compound within the pill, as anyone can make their own pills which copy the features of a well-known brand.
Pills sold illegally on the street don't always have MDMA as the only active ingredient. Black market pills most likely contain methamphetamine, but have been found to contain analogues such as MDEA, MDA and MBDB, and occasionally other unrelated psychoactive additives such as amphetamines (speed), DXM, ephedrine, PMA, caffeine, ketamine (Special K), and others.
ketamine
While overdose from MDMA itself is rare, many more toxic substances are often sold as ecstasy, and overdose or other adverse reaction to adulterants is not uncommon. MDMA appears to be one of the most commonly adulterated drugs.
Many legal pills such as aspirin, paracetamol (acetaminophen), or even canine heartworm tablets have had the letter E scratched into them and been sold as ecstasy, for enormous profit. (This is a minor plot device in the movie Go.) Such false labeling can have deadly results, as a significant number of people are allergic to aspirin. Paracetamol is fairly hepatotoxic and can cause significant liver damage or death if taken in large doses, as might happen to a person taking four or five tablets in quick succession, thinking the tablets to be ecstasy.
Although full and proper characterization of ecstasy pills requires advanced lab techniques such as Gas chromatography-mass spectrometry, it is also possible to use a less accurate presumptive alkaloid test known as the Marquis reagent. DanceSafe sells testing kits, and includes an extensive database of photographs of different pills, along with the results of a laboratory analysis of their contents. EcstasyData.org [http://www.ecstasydata.org/] is a non-profit site that tests the purity of street pills and compiles results. Most blackmarket pills are made in basement labs and are dangerous because of house hold chemicals near by.
Effects
Neurological effects
Serotonin is one of the chemicals responsible for mood and pleasure. MDMA's main action is believed to cause serotonin stores in the brain to release abnormally large quantities of serotonin into the synapses during the 4 to 6 hour high, which is responsible for the primary subjective effects. MDMA also raises dopamine and norepinephrine levels and promotes the release of the hormone prolactin. These effects are primarily due to MDMA's action on the monoamine transporters, SERT (serotonin transporter), DAT (dopamine transporter) and NET (norepinephrine transporter).
Other short-term effects
Apart from the dangers from impurities, the primary acute risks of taking MDMA are allergic reaction, which is extremely rare, and dehydration. Like many amphetamines, MDMA can mask the body's normal thirst and exhaustion responses, particularly if a user is dancing or is otherwise physically active for long periods of time without hydration. MDMA is known to temporarily reduce the body's ability to regulate its core temperature, and in high-temperature surroundings (e.g. clubs) combined with physical exertion this may lead to hyperpyrexia if precautions are not taken to remain cool. In sedentary therapeutic use, incidence of dehydration is not statistically significant. Experts do warn regular users of the drug in more physically active social settings to be cognizant of water intake. While dehydration is undesirable, there also have been a very small number of users overly concerned about hydration drinking excessive water and suffering from water intoxication and associated
hyponatremia (dilution of the blood that can cause swelling of the brain). This is what caused the death of British teen Leah Betts, which may be the world's most widely publicised MDMA-related fatality.
Some users also report decreased libido or impotence, although studies in this area have provided conflicting results [http://www.idmu.co.uk/esex.htm].
Long-term effects
Long-term effects are still unknown and heavily debated among scientists.
There are several reports of Hallucinogen Persisting Perception Disorder being induced by MDMA. In some cases, the disorder appears to be permanent. The disorder seems to occur in only a small percentage of users, and its mechanism of causation is unknown.
The central criticism of MDMA is the "what goes up must come down" theory, which deals with MDMA's artificial boosting of serotonin levels as causing the inverse effect of diminishing of the brain's natural production of serotonin — producing symptoms of acute or chronic depression. However while mood and serotonin levels are known to be related, its not yet clear by what chain of mechanisms serotonin causes changes in mood, and in turn, which effects can be linked to MDMA.
Some experiments indicate that continuous use at very high doses may lead to the synaptic terminals of serotonin neurons being damaged. The precise mechanism of this action is unknown, but recent evidence (Jones 2004; Miller 1997; Monks et al. 2004) suggests that the metabolic breakdown of MDMA includes the formation of reactive oxygen species (ROS), chemicals known to cause oxidative cell damage when taken up into the serotonin neurons.
This effect has been observed in the brains of rats, where the serotonin terminals of animals who are given extremely high doses of MDMA over a prolonged period of time (usually one to two orders of magnitude greater than a typical human dose) become withered and useless. This hypothesis is supported by the fact that the administration of selective serotonin reuptake inhibitors ("SSRIs", which bind to the serotonin cell's reuptake transporters and thus block ROS from entering the serotonin cells) along with or immediately following MDMA seems to completely block neuron damage in rats given MDMA.
For this reason many users self-administer an SSRI while, or shortly after taking MDMA, in an attempt to prevent possible neurotoxicity. These SSRIs are typically antidepressants such as Prozac or Zoloft. It should be noted, however, that MDMA use in conjunction with a different class of antidepressants, namely Monoamine oxidase inhibitors, is strongly contra-indicated due to danger of serotonin syndrome.
Many users also attempt to replenish the deficit of serotonin which follows the use of MDMA by administering 5-HTP. The serotonin precursor 5-HTP, which is commerically available as a dietary supplement, reportedly supplies the user with more of the raw materials to synthesize the neurotransmitter.
Because MDMA's neurotoxicity is known to be highly dependant on its metabolic disposition (Jones 2004; de la Torre & Farré 2004), it is not known whether experiments in rats and monkeys have any direct bearing on human users.
Considerable research has been done into possible cognitive-behavioral deficits among ecstasy users but data have been largely inconclusive. At least two meta-analyses of these studies have been completed (Morgan 2000; Sumnall & Cole 2005). Morgan's analysis of 17 studies showed that ecstasy users had a slight tendency to be more impulsive and depressed than controls. Sumnall and Cole's analysis showed a slight increase in the prevalence of depressive symptoms in ecstasy users over controls. Of course, in retrospective studies like these we are always faced with a chicken-or-egg question: did these impulsive and depressed people use ecstasy to self-medicate or did otherwise normal people become depressed and impulsive after using ecstasy? This question has not been answered. Moreover, such research is problematic as ecstasy users are much more likely than control subjects to have taken other drugs in addition to ecstasy. This makes it difficult for researchers to establish a direct causal relationship.
Although some experimental evidence exists indicating that long-term ecstasy users experience memory difficulties, a large study in 2002 (Strote et al.) showed that ecstasy users in 4-year colleges have GPAs which do not differ significantly from those of non-users.
According to one study, MDMA use has led to to rhabdomyolysis (muscle breakdown) as a consequence of MDMA-induced hyperpyrexia (abnormally high body temperature). Rhabdomyolysis can cause renal failure and death. The author notes the "degree to which the seriousness of the effects can be dependent on environmental factors other than the drug concentration" in describing the fact that of the fatalities, blood concentrations of the drug spanned a large range. This notwithstanding, the author also notes that "Most of the cases of serious toxicity or fatality have involved blood levels... up to 40 times higher than the usual recreational range." (Kalant H., 2001) [http://www.cmaj.ca/cgi/content/full/165/7/917]
Systemic effects
Other effects include:
- Pupil dilation with attendant photosensitivity and color perception
- Jaw clenching or bruxism ("gurning" or "grinding")
- Shutter vision (nystagmus)
- General restlessness
- Loss of appetite/taste sensation changes
- Lack of focus / concentration
- Tingling
- Sweaty palms
- Increased heart rate
Ecstasy and Parkinson's
Research at the University of Manchester indicates that ecstasy dramatically reduces tremors in patients receiving L-DOPA treatment for Parkinson's Disease.
In a now-retracted study, a research team led by Dr. George A. Ricaurte at Johns Hopkins University implicated MDMA as a cause of Parkinson's-like brain abnormalities in monkeys, suggesting that a single use of MDMA caused permanent and serious brain damage. These claims were hotly disputed by physicians, therapists, and other experts, including a team of scientists at New York University. Criticisms of the study included its use of injection rather than oral administration; that this type and scale of damage (>20% mortality) would translate to hundreds of thousands or millions of deaths which had not materialized in the real world amidst extremely broad global MDMA usage; and, perhaps most important, that other research teams could not duplicate the study's findings.
On September 6, 2003, Dr. George A. Ricaurte and his team announced that they were retracting all results of their commonly cited and controversial study. The researchers said that the labels on the drugs had been somehow switched, and they had inadvertently injected their experimental monkeys and baboons with methamphetamine instead of MDMA. The chemical supplier, Research Triangle Institute, has publicly claimed that the proper drug was supplied, and Ricaurte has yet to pursue them for their alleged error.
Ricaurte had also come under fire for supplying PET scans to the U.S. Office of National Drug Control Policy that were used in anti-drug literature (Plain Brain/Brain After Ecstasy) that seemed to suggest MDMA created holes in human brains, an implication that critics called misleading. Ricaurte later asked the Agency to change the literature, citing the "poor quality" of the images.
Ecstasy and the law
Use, supply and trafficking of ecstasy are currently illegal in most countries. In the United States, MDMA was legal and unregulated until the May 31st 1985, at which time it was added to DEA Schedule I, for drugs deemed to have no medical uses and a high potential for abuse. During DEA hearings to criminalize MDMA, most experts recommended DEA Schedule III prescription status for the drug, due to its beneficial usage in psychotherapy. The judge overseeing the hearings, Francis Young, also made this recommendation. Nonetheless, DEA classified it as Schedule I.
That same year, the World Health Organization's Expert Committee on Drug Dependence recommended that MDMA be placed in Schedule I of the Convention on Psychotropic Substances. Unlike the Controlled Substances Act, the Convention has a provision (in [http://www.incb.org/e/conv/1971/articles.htm#7 Article 7(a)]) that allows use of Schedule I drugs for "scientific and very limited medical purposes". The Committee's report stated[http://www.ecstasy.org/books/e4x/e4x.ap.01/e4x.ap.01.015.html]:
:It should be noted that the Expert Committee held extensive discussions concerning therapeutic usefulness of 3,4 Methylenedioxymethamphetamine. While the Expert Committee found the reports intriguing, it felt that the studies lacked the appropriate methodological design necessary to ascertain the reliability of the observations. There was, however, sufficient interest expressed to recommend that investigations be encouraged to follow up these preliminary findings. To that end, the Expert Committee urged countries to use the provisions of article 7 of the Convention on Psychotropic Substances to facilitate research on this interesting substance.
In the United Kingdom, MDMA is Schedule I/Class A, making it illegal to sell, buy, or possess without a license. Penalties include a maximum of seven years and/or unlimited fine for possession; life and/or unlimited fine for production or trafficking. A mandatory seven year sentence is now the penalty for a third conviction for trafficking.
Medical use
In 2001, the FDA approved MDMA for research with patients suffering from post-traumatic stress disorder. In March of 2004, the DEA issued its first Schedule I possession licenses for those conducting research under the FDA approval; research is being conducted through the Multidisciplinary Association for Psychedelic Studies (MAPS) on veterans from the U.S. invasion of Afghanistan, rape victims, and cancer patients. For further information on this, see [http://www.maps.org/research/mdma/ MAPS's MDMA Research Information] and the recent article from [http://www.msnbc.msn.com/id/7613571/site/newsweek/ MSNBC/Newsweek].
Safety
The illegality of this drug in many countries makes exact study of its effects difficult. Some of the effects ascribed to ecstasy, which may or may not be conclusive, are the following:
- Because of its illegality, the dose and purity of a pill advertised as ecstasy may be stronger than is desired or may be unsafe.
- Ecstasy affects the regulation of the body's internal systems. Continuous dancing without sufficent breaks or drinks can lead to dangerous overheating and dehydration. Drinking too much water without consuming a corresponding amount of salt can lead to hyponatremia or Water intoxication.
- The use of ecstasy can exacerbate depression and produces temporary depression as an after-effect of its use.
- The use of ecstasy can be very dangerous when combined with other drugs (particularly monoamine oxidase inhibitors (MAOIs) and antiretroviral drugs).
- Because it substantially affects perception, concentration, and motor skills, it is dangerous to operate heavy machinery or motor vehicles when using ecstasy.
- Long-term after-effects are greatly exacerbated by high doses and frequent use.
- A small percentage of users may be highly sensitive to MDMA; this may make first-time use especially hazardous. This includes but is not limited to people with congenital heart defects, and a small percentage of people who lack the proper enzymes to break down the drug.
See also
- Sextasy
- Empathogen/Entactogen
- Amphetamine
- Phenethylamines
- Psychedelic therapy
- Psychoactive drug
- RAVE Act
- Retracted article on neurotoxicity of ecstasy
- Leah Betts & Anna Wood (people who have died as a result of drinking too much water while on ecstasy)
External links
Media
- Conant, Eve. "[http://www.msnbc.msn.com/id/7613571/site/newsweek/ Ecstasy: A Possible New Role for a Banned Club Drug]." Newsweek, May 2, 2005.
- [http://video.fox6.com/launcher/28793 Generation on X: An undercover look at the growing trend of teens using Ecstasy] FOX News, April 26, 2005.
- Weiss, Rick. "[http://www.washingtonpost.com/wp-dyn/articles/A27716-2004Dec26.html 'Ecstasy' Use Studied to Ease Fear in Terminally Ill]." The Washington Post, December 27, 2004.
- Philipkosk, Kristen. "[http://www.wired.com/news/medtech/0,1286,65025,00.html Wired News: Long Trip for Psychedelic Drugs]." Wired, September 27, 2004.
- Philipkosk, Kristen. "[http://www.wired.com/news/business/0,1367,62506,00.html DEA Approves Ecstasy Tests]." Wired, March 2, 2004.
- Darman, Jonathan. "[http://www.msnbc.com/news/1001897.asp Out of the Club, Onto the Couch ] Newsweek.com, December 5, 2003. - An interview with NYU's Dr. Julie Holland
- Weiss, Rick. "[http://www.washingtonpost.com/wp-dyn/articles/A33096-2003Sep5.html Results Retracted on Ecstasy Study]." The Washington Post, September 6, 2003.
- Recer, Paul "[http://www.cbsnews.com/stories/2002/09/26/health/main523423.shtml Ecstasy-Parkinson's Connections?]." CBS News, September 26, 2002.
Academic
- [http://www.maps.org/research/mdma/index.html The Multidisciplinary Association for Psychedelic Studies (MAPS): MDMA project] MAPS is at the forefront of human MDMA research, having obtained FDA permits for two studies administering MDMA to human volunteers in order to explore the drug's potential psychiatric benefits (one study is already underway.)
- [http://TheDEA.org/neurotoxicity.html TheDEA.org's extensive critique/review of the evidence against MDMA ('ecstasy') causing brain damage at common recreational doses.]
- [http://www.dancesafe.org/slideshow/index.html This is your brain on Ecstasy] - A slideshow that illustrates the neuropharmacokinetics of Ecstasy (how the drug affects the brain.) Some of the information on this page is at present (July 2005) outdated.
- [http://www.erowid.org/library/books_online/pihkal/pihkal109.shtml PiHKAL entry]
- [http://www.maps.org/sys/w3pb.pl?face=simple/ The MAPS research library, containing downloadable copies of most of the MDMA and LSD research ever done.]
General
- Ectasydata.org [http://www.ecstasydata.org/] A non-profit pill testing database.
- [http://www.maps.org Multidisciplinary Association for Psychedelic Studies]
- [http://www.pillreports.com Pillreports ] - The definitive Ecstasy database that is updated with "trip" reports and pictures daily.
- [http://www.tripproject.ca/march/drugContent.php?info=ecstasy User-friendly info on Ecstasy] provided by the TRIP! Project, Toronto Canada
- [http://www.thegooddrugsguide.com/ecstasy/index.htm The Good Drugs Guide] - The Good Drugs Guide - Ecstasy
- [http://www.dancesafe.org DanceSafe] - a risk reduction site with lots of information on Ecstasy. Includes a large database of photographs of different pill types, along with laboratory analysis of what was actually found in the pill.
- [http://www.dancesafe.org/slideshow/ This is your brain on Ecstasy: MDMA Neurochemistry Slideshow] Slideshow that shows the chemical reactions in the brain that cause the effects of MDMA - hosted by Dancesafe.
- [http://www.erowid.org/chemicals/mdma/mdma.shtml Erowid's Ecstasy page] - lots of information
- [http://www.ndh.org.uk/facts_ecstasy.html UK National Drugs Line factsheet on Ecstasy]
- [http://www.acde.org/common/ecstasy.htm American Council for Drug Education factsheet on Ecstasy]
- http://www.ecstasy.org
- [http://www.mdma.net Utopian Pharmacology]. Detailed essay discussing the history and uses of MDMA
- [http://www.mdma.net/index.html] A paper on MDMA including long history section
- [http://TheDEA.org TheDEA.org] An ecstasy user's guide with detailed discussions of risks and scientific research.
References
- de la Torre, Rafael et al. (2000), Non-linear pharmacokinetics of MDMA (`ecstasy') in humans. Br J Clin Pharmacol, 2000; 49(2):104-9
- de la Torre, Rafael & Farré, Magí (2004). Neurotoxicity of MDMA (ecstasy): the limitations of scaling from animals to humans. Trends in Pharmacological Sciences 25, 505-508.
- Jennings, Peter. Ecstasy Rising, ABC television documentary. 2004-01-04.
- Jones, Douglas C. et al. (2004). Thioether Metabolites of 3,4-Methylenedioxyamphetamine and 3,4-Methylenedioxymethamphetamine Inhibit Human Serotonin Transporter (hSERT) Function and Simultaneously Stimulate Dopamine Uptake into hSERT-Expressing SK-N-MC Cells. J Pharmacol Exp Ther 311, 298-306.
- Kalant H. (2001) The pharmacology and toxicology of "ecstasy" (MDMA) and related drugs. CMAJ. Oct 2;165(7):917-28. Review. PMID 11599334 [http://www.cmaj.ca/cgi/content/full/165/7/917 Full Text]
- Miller, R.T. et al. (1997). 2,5-Bis-(glutathione-S-yl)-alpha-methyldopamine, a putative metabolite of (+/-)-3,4-methylenedioxyamphetamine, decreases brain serotonin concentrations. Eur J Pharmaco. 323(2-3), 173-80. Abstract retrieved Apr 17, 2005, from PubMed.
- Monks, T.J. et al. (2004). The role of metabolism in 3,4-(+)-methylenedioxyamphetamine and 3,4-(+)-methylenedioxymethamphetamine (ecstasy) toxicity. Ther Drug Monit 26(2), 132-136.
- Morgan, Michael John (2000). Ecstasy (MDMA): a review of its possible persistent psychological effects. Psychopharmacology 152, 230-248.
- Strote, Jared et al. (2002). Increasing MDMA use among college students: results of a national survey. Journal of Adolescent Health 30, 64-72.
- Sumnall, Harry R. & Cole, Jon C. (2005). Self-reported depressive symptomatology in community samples of polysubstance misusers who report Ecstsay use: a meta-analysis. Journal of Psychopharmacology 19(1), 84-92.
Category:Alkaloids
Category:Entactogens and Empathogens
Category:Class A drugs
Category:Schedule I controlled substances
Category:Psychedelic phenethylamines
List of street names of drugs
A street name is a slang name given to a drug other than its popular or chemical names. Street names for drugs drastically change from place to place and time to time, and no absolute reliance should ever be placed on them. This list covers only English terms, though many such terms exist in other languages.
- Booze
- Brews
- Brewskis
- Cold One
- Crunk Juice
- Grandpa's Cough Syrup
- Grog -- Australian slang
- Hooch
- Hard Stuff
- Ice cold lemonade
- Jesus Blood (red wine) -- coined by Michael Jackson
- Jesus Juice (white wine) -- coined by Michael Jackson
- Sauce
- Billy -- generally Amphetamine Sulphate
- Dexies -- from the brand name Dexedrine or the chemical name Dexamphetamine sulphate,
- Speed -- generally Amphetamine Sulphate
- Whiz -- generally Amphetamine Sulphate
- Animal -- play on 'Amyl'
- DVD-Cleaner
- Liquid gold -- descriptive
- Locker room
- Poppers -- may be any of Amyl nitrite, Alkyl nitrites, or Butyl nitrite
- Rush
- Stephen Armstrongs
- Arnolds -- from Arnold Schwarzenegger's known steroid use in the past
- Gym candy
- Iron Brew -- steroids such as Durabolin, Stanozolol, Dianabol; this should not be confused with the soft drink Irn-Bru
- Juice -- steroids in general
- Roids -- steroids in general
- Bars -- 2mg stick shaped pills, brand name Xanax, chemical name Alprazolam
- Downers -- generic street name for benzodiazepines or barbiturates
- Footballs -- .25-1mg football shaped pills, brand name Xanax, chemical name Alprazolam
- Forget-Me-Pill -- chemical name Flunitrazepam
- Jellies -- chemical name Temazepam
- La Roche -- chemical name Flunitrazepam
- Mexican Valium - chemical name Flunitrazepam
- Moggies -- brand names: Mogodon, Nitrados, Remnos, Unisomnia, chemical name
- R-2 -- chemical name Flunitrazepam
- Rib -- chemical name Flunitrazepam
- Roachies -- chemical name Flunitrazepam
- Roche -- chemical name Flunitrazepam
- Roofies -- chemical name Flunitrazepam
- Rope -- chemical name Flunitrazepam
- Rophies -- chemical name Flunitrazepam
- Ropies -- chemical name Flunitrazepam
- Ruffies -- chemical name Flunitrazepam
- Rugby Balls -- chemical name Temazepam
- Sticks -- 2mg stick shaped pills, brand name Xanax, chemical name Alprazolam
- Terms -- chemical name Temazepam
- Vallies -- brand name Valium, chemical name Diazepam
- Al Green
- Afi -- short for Afgahni variety of marijuana characterized by seedless buds
- B -- shortened form of Bud
- Bad One -- refers to high-quality cannabis
- Banza -- common term in Brazil
- Bammer -- bad marijuana
- Bank Head Bud
- BC Bud -- hydroponically grown marijuana from British Columbia, usually Vancouver, known for its high THC content
- Beaster -- marijuana from Vancouver, British Columbia, Canada
- Black -- marijuana with tobacco mixed in; more popular in Europe
- Blaze -- to smoke marijuana
- Blowhead
- Blunt -- a marijuana cigar; named for the Philly Blunt
- Bob Hope -- from the Boston area
- Bomb -- high potency marijuana
- Boom
- Bowgma-Chuff
- Bread -- a small amount can be referred to as a slice; bread is said to be thrown when ingested
- Bud -- the buds of the cannabis plant
- Buddha
- Bunk -- low quality grass
- Bush
- Cann -- short for Cannabis
- Cereal -- bowl of "cereal" used in telephone conversation to avoid illicit terminology
- CD's -- SE New England slang that was popularized on public access TV
- Cheebong
- Chrin
- Chucky -- (NY) Bronx term for marijuana that is of low to average quality with a slow burn
- Chronic or Chron -- high quality marijuana (Also used to refer to marijuana laced with crack)
- Clone -- seedless marijuana
- Cocktails -- mix of hash and skunk in one spliff
- Cocoa Puff--marijuana mixed with cocaine, usually sprinkled on top of a bowl or in a spliff
- Collie Weed -- Jamaican terminology
- Conversational Bread Throwing -- a euphemism for smoking marijuana, especially in a group
- Creeper Weed (or Creeper) -- marijuana that has a high that comes on slowly
- Crippy - term used in Florida locales, referring to any general high-grade cannabis (Compare to "regs" - regular-grade cannabis )
- Cush (or Kush) -- ancient variety from the Kingdom of Cush in what is now Sudan; it grows wild along the banks of the upper Nile River
- Daddy
- Dagga -- South African slang
- Dak
- Dank -- potent marijuana
- Dark -- marijuana that is darker than normal
- Diggity -- another name for dank, used heavily in South Georgia.
- Dime -- a 10 dollar bag of marijuana (usually of lower quality)
- Dirt -- cannabis of a lower quality; also, marijuana that is grown in dirt and is not hydroponically grown (also known as Dirtweed)
- Dirty Dank
- Ditchweed -- Schwag, etc.
- Doobie or Doob -- a spliff
- Dope -- sometimes a generic term for illegal drugs in general
- Doshia (sometimes spelled Dolja)
- Draw
- Dro -- short for hydro
- Dub -- a $20 bag of marijuana
- Dustwallow Marsh -- named after Dustwallow Marsh in World of WarCraft; high quality cannabis
- Electric Puha -- from New Zealand, named after the Puha plant
- Fat Sack -- a large quantity of marijuana found within a single bag
- Fire -- very potent marijuana; also, marijuana that produces a strong burning sensation when deeply inhaled
- Flack Juice
- Fruit
- Funk
- Gage
- Ganj -- a shortened variant of Ganja
- Ganja -- a Caribbean English term; rather common in Jamaica
- Gerp
- Gear -- a general term for the drug; used with most forms the drug comes in
- Good Goods -- from Charles Mann
- Gran
- Grango Bango -- a general loosely used term
- Grass
- Green
- Green Funk
- Half A Sandwich -- 1/2 ounce of cannabis
- Hameni
- Hash -- short for hashish
- Headies
- Heady Nugs
- Hemp
- Herb -- from the appearance of dried cannabis; extensively used in Jamaica
- Herbals (sometimes colloquially spelled as Herbalz)
- High
- High-Grade -- expensive marijuana with a high THC content; often Kind-Bud
- Hog-Leg -- a fat joint or blunt that resembles the stubby/thick leg of a hog
- Home Grown -- fresh picked marijuana
- Hydro -- short for hydroponics, a method of growing marijuana indoors using a nutrient solution in lieu of soil
- Indo
- Ish
- J -- abbreviation for a marijuana joint
- Jason Wheatley -- Chester term (popular with students from the north east)
- Judy Fly -- a marijuana joint or cigar with a bit of cocaine powder added
- K.B. -- short for Kind-Bud (also spelled Kynd-Bud)
- K.G.B. -- killer-green-bud
- Killer -- kind bud
- Kilroy
- Kind-Bud -- a high-grade and usually expensive strain of marijuana; often grown indoors
- Kind
- Kraut
- Kronic -- see "Chronic"
- Kryptonite -- from the green substance that weakens Superman
- Kynd -- a European variant of Kind
- L -- a marijuana cigar (see Blunt)
- La-LaLa
- Left Handed Cigarette -- a marijuana joint
- Lid -- a bag of weed
- Lows -- low-grade marijuana that is usually cheap and not very potent (see Schwag)
- M
- Marihuana (variant of Marijuana)
- Marijuana -- word originates in Mexican Spanish
- Mary
- Mary Jane -- literal translation of Marijuana
- Methtical -- hip-hop slang from the rap-group The Wu-Tang Clan (see Method Man)
- Method
- Mid-Grade -- marijuana which is above-average but below high-grade in terms of potency
- Middies -- a variant of Mid-Grade (also spelled Middys)
- Mint
- M.J. -- short for Mary Jane
- Mota
- Muggles
- Murphy
- Neihe -- pronounced "near-he"; originated in Trinidad (Monos Island); neihe is usually shouted out in the duttiest fashion possible
- Nuggets -- resinous Nuggets of cannabis buds
- Nuggs -- shortened variant of Nuggets
- Nugglets -- comic variant of Nuggs
- Old Toby
- Out-Do
- The Peeping Jesus
- Phat Sack -- a large quantity of marijuana found within a single bag
- Piff, or Mr. Piff
- Piz -- a Croatian word for an approx. 7 grams of marijuana (worth $8)
- Politics
- Poke Smot -- a semi-spoonerism, as opposed to smoke pot; used frequently in Waterloo, Ontario
- Pot -- from Mexican Spanish Potiguaya, cannabis leaves; very common slang
- Puff
- Purps -- short for "Purple Haze," an extremely potent strain
- Rasta Plant -- from the Rastafari movement
- Reef -- a shortened variant of Reefer
- Reefer
- Relish
- Rope -- a joint, "smoke a rope"
- Schwag -- average to below-average marijuana which is usually very cheap; schwag is often smuggled in to the USA from Mexico; many teenagers begin their "marijuana experience" smoking schwag because it is extremely cheap and very accessible to the general public
- Sensi -- a shortened variant of Sensemilla
- Sensemilia -- Spanish sin semilla, "without seeds"; unfertilized female cannabis buds
- Sess (sometimes spelled as Cess)
- Shake -- loose cannabis flakes that have fallen off of the bud into the bottom of the bag; also known as scrapes
- Shit
- Shizz
- Shizznit -- combination of Shizz and Shit
- Shrubs
- Skunk -- a particular cannabis strain; from its distinctive, skunky smell
- Smoke
- Spliff -- a large joint
- Stank -- highly aromatic marijuana
- Stash
- Stick -- $25 worth of marijuana, also called a Twenty-Fiver
- Sticky -- marijuana that is particularly resinous
- Stress -- lower grade marijuana characterized by the presence of seeds and stems
- Striijj -- pronounced "Streeeege," from slang used in Toronto, Canada
- Stuff -- often used over the phone for those buyers/sellers paranoid or wary of being busted by the police
- Tea -- early 20th-century slang
- Texas Red
- That Shit
- The Wizard
- Throw Bread -- to smoke marijuana; one can also toss-a-slice
- Tical -- hip-hop slang from the rap-group The Wu-Tang Clan
- Trees -- from the resemblance of marijuana buds to leafy tree-greens
- Twamp -- a $20 bag of marijuana
- Tweed
- Twenty-Fiver -- $25 worth of marijuana, also called a stick
- Wacky Baccy
- Wacky Tabacky -- from tobacco
- Wacky Weed
- Weed -- very common slang
- White Rhino -- marijuana laced with cocaine
- Yaa
- Yameen
- Yoda
- Zoot -- A joint of marijuana. Popular in the UK
Cheese
- Bing or Bing Crosby -- Boston area
- Blow
- Bolivian Marching Powder
- Booger Sugar
- C
- California Cornflakes
- Chabbie
- Charlie
- Chinese Sky Candy
- Ching -- resembling a cash-register, because of how expensive cocaine is
- Co-ca-ee-na (phonetic)
- Coke -- shortened form of cocaine
- Columbian Dancing Dust
- Columbian Foot Soldiers
- Cuch
- Devils Dandruff
- Flake
- Happy Trails
- Hocus-Pocus
- Hydro
- Kitty
- Lady C
- Lines
- Lucifer Left-Nostril
- Nose Candy
- Powder -- self descriptive
- Shnazzle
- Skeeter
- Sleigh Ride
- Snow -- cocaine as a powder resembles very fine snow (see Ski Bunnies)
- Snow Angels
- Soft
- The White Lion
- Tonys -- after Tony Montana from Scarface
- White
- White Lady
- Yao -- pronounced "yay-O"
- Yale
- Yak -- Southwestern colliquial.
- Yay
- Yeyo -- from Scarface: "Chichi, get the lleyo" (also featured in hip-hop lyrics)
- Black
- Black Tar -- from a certain variety
- Bobby Brown
- Boy
- Brown Sugar
- Cheeba
- China White
- Dog Food
- Dookey Rocks
- Dragon -- when smoked, the thick smoke of heroin is said to resemble the tail of a dragon (hence Chasing the Dragon)
- Golden Brown -- from the color of heroin
- Goop
- H -- shortened form of Heroin
- Harry
- Hero
- Hop
- Horse
- Junk
- Kaka Water
- Lady H
- Noddy Brown
- Pepper
- Scag
- Smack -- from the action of smacking the arm to produce a prominent vein in which to inject the drug
- Tar
- Adam
- E
- Ecstasy
- Beans
- Doves
- Jack and jills, or simply Jills - English Cockney rhyming slang
- Madman
- Mandy
- Mitsu's- named after the infamous Mitsubishi Ecstasy pills of the late 1990s to early 2000s
- Pills
- Sweets
- Thizz
- X
- Cat Tranquilizer, Horse Tranquilizer, etc -- from its use as a veterinary anaesthetic
- K -- shortened form of Ketamine
- Kenny
- K-Hole -- disassociated hallucinogenic state at higher doses
- Kitty
- Regretamine
- Special K -- humorous; from the breakfast cereal of the same name
- Vitamin K
- Chat
- Qat
- Quaadka
- Acid
- Acid tabs
- Alice -- from Alice in Wonderlands psychedelic and hallucinatory adventures
- Blotters -- see tabs
- Lavender
- Lucy in the sky with diamonds
- Paper
- Tabs -- LSD is sometimes blotted onto sheets of paper, cut up into little squares called tabs
- Timothy Leary Ticket
- Trade names -- e.g. Strawberries, Orange Sunshine, Felix; tabs are often illustrated, and specific batches named after the illustration or colour of paper used.
- Trip
- Trips -- note than an LSD experience is known as a trip; being on LSD is known as tripping
- Uncle Sidney -- contraction of A-cid
- Window Pane
- Meth
- Phy -- from Physeptone, a brand name for methadone
- Amp -- from the "amped-up" or "charged-up" feeling that a person feels when on crystal-meth
- Champagne
- Crank -- non-crystalline methamphetamine powder prepared for insufflation or injection
- Crystal -- from the crystalline form of pure methamphetamine
- Crystal-Meth
- Christina
- Crack -- from "Crank"
- Dope -- a term for drugs in general but also used for meth
- Gak
- Geek
- Goose-Egg
- Go or Go Fast
- Go Pills -- military slang, especially pilots (see history of WWII: Japan, Germany, USA)
- Ice -- from the appearance of crystalline methamphetamine, resembling ice
- Jib -- Canadian Meth
- Meth
- P
- Pure
- Ryan
- Shabu -- Japanese street name
- Shit
- Speed -- applicable also to any stimulants of the amphetamine class
- Tanner
- Tina -- from 'Christina'
- Tweak
Other
- Eve -- MDEA
- Gary -- MDMA from rhyming slang for [http://en.wikipedia.org/wiki/Gary_Ablett Gary Ablett], Tablet
- GHB -- Gammahydroxybutyrate
- GBH -- GHB from 'Greivous Bodily Harm,' highlighting its use as a date rape drug.
- Hippy crack -- Nitrous Oxide
- Liquid Ecstacy -- Gammahydroxybutyrate
- Sextasy -- a slang term for the combination of the drugs MDMA (ecstasy) and sildenafil citrate (aka Viagra®)
- Whippets -- Nitrous Oxide
- Blues and Yellas -- from the color of the valium
- DFs -- from DF118, a brand name of the chemical Dihydrocodeine
- Dikes -- from Diconal a brand name for Dipipanone and cyclizine
- Dikies -- from Diconal a brand name for Dipipanone and cyclizine
- Diffs -- brand name DHC Continus, chemical name Dihydrocodeine
- Hillbilly Heroin -- Oxycodone
- Nubian -- from Nalbuphine hydrochloride
- Tems -- brand name Temgesic, chemical name Buprenorphine
- Angel Dust
- Dust
- Hog
- PCP
- Rocketfuel
- Sherm or Sherms
- Boomers
- Fun Gus
- Fun Guys
- Fungus
- Gus
- Magic Mushrooms
- Magick Mushrooms
- Mucks
- Muggers
- Mush
- Mushies
- Shrooms
- Shroomies
- Umbrellas
- Zoomers
External links
- [http://www.weeddealer.com/dopelist/a.htm WeedDealer] From A to Z Drug Terminology List
- [http://www.whitehousedrugpolicy.gov/streetterms/default.asp Street Terms: Drugs and the Drug Trade (anti-drug site)]
- [http://www.drugs-about.com Drugs catalog]
- Wiktionary Appendix of Cannabis Slang
- [http://www.erowid.org/psychoactives/slang/slang.shtml Erowid Drug Slang & Terminology Vault]
Category:Pharmacologic agents
Category:Slang
Category:Drugs
Category:Illegal drugs
Phenethylamine
Phenethylamine (Phenylethylamine) is an alkaloid and monoamine. In the human brain, it is believed to function as a neuromodulator or neurotransmitter. A colorless liquid that forms a solid carbonate salt with carbon dioxide (CO2) upon exposure to air, phenethylamine in nature is synthesized from the amino acid phenylalanine by enzymatic decarboxylation. It is also found in many foods, especially after microbial fermentation, e.g. in chocolate.
It has been suggested that phenethylamine from food (e.g. chocolate) may have psychoactive effects in sufficient quantities. However, it is quickly metabolized by the enzyme MAO-B, preventing significant concentrations from reaching the brain.
Substituted phenethylamines are a broad and diverse class of compounds that include neurotransmitters, hormones, stimulants, hallucinogens, entactogens, anorectics, bronchodilators, and antidepressants.
The phenethylamine structure can also be found as part of more complex ring systems such as the ergoline system of LSD or the morphinan system of morphine.
Substituted phenethylamines
morphine
Substituted phenethylamines carry additional chemical modifications at the phenyl ring, the sidechain, or the amino group:
- Amphetamines are phenethylamines carrying an alpha-methyl (α-CH3) group at the sidechain carbon atom next to the amino group.
- Catecholamines are phenethylamines carrying two hydroxy groups in positions 3 and 4 of the phenyl ring. Examples are the hormones and neurotransmitters dopamine, epinephrine (adrenaline), and norepinephrine (noradrenaline).
- The aromatic amino acids phenylalanine and tyrosine are phenethylamines carrying a carboxyl group (COOH) in alpha position.
Pharmacology
Many substituted phenethylamines are pharmacologically active drugs due to their similarity to the monoamine neurotransmitters:
- Stimulants like the plant alkaloids ephedrine and cathinone and the synthetic drugs amphetamine (speed, benzedrine) and methylphenidate.
- Hallucinogens like the plant alkaloid mescaline and the synthetic drug 2C-B.
- Empathogen/Entactogens like MDMA (ecstasy) and MDA.
- Anorectics like phentermine, fenfluramine, and amphetamine.
- Bronchodilators like salbutamol and ephedrine.
- Antidepressants like bupropion and the monoamine oxidase inhibitors phenelzine and tranylcypromine.
Substitution table
Some of the more important phenethylamines are tabulated below. For simplicity the stereochemistry of the sidechain is not covered in the table. Hundreds of other simple synthetic phenethylamines are known. This is due in part to the pioneering work of Alexander Shulgin, much of which is described in the book PiHKAL.
500px
See also
- Catecholamines
- PiHKAL
- Alexander Shulgin
External links
- [http://www.erowid.org/library/books_online/pihkal/pihkal.shtml Book II of PiHKAL] online
- Review and summary of PiHKAL, including table of 300+ phenethylamines: [http://www.erowid.org/archive/hyperreal/drugs/psychedelics/phenethylamines/pihkal.review ascii] [http://www.erowid.org/archive/hyperreal/drugs/psychedelics/phenethylamines/pihkal.review.ps postscript]
- [http://www.erowid.org/archive/rhodium/chemistry/pihkaltour/ A Structural Tour of PiHKAL]
Categorization
Category:Phenethylamines
Dopamine
Dopamine is a chemical naturally produced in the body. In the brain, dopamine functions as a neurotransmitter, activating dopamine receptors. Dopamine is also a neurohormone released by the hypothalamus. Its main function as a hormone is to inhibit the release of prolactin from the anterior lobe of the pituitary.
Dopamine can be supplied as a medication that acts on the sympathetic nervous system, producing effects such as increased heart rate and blood pressure. However, since dopamine cannot cross the blood-brain barrier, dopamine given as a drug does not directly affect the central nervous system. To increase the amount of dopamine in the brain of patients with diseases such as Parkinson's disease and Dopa-Responsive Dystonia, a synthetic precursor to dopamine such as L-DOPA can be given, since this will cross the blood-brain barrier.
Biochemistry
Dopamine has the chemical formula (C6H3(OH)2-CH2-CH2-NH2). Its chemical name is 4-(2-aminoethyl)benzene-1,2-diol and it is abbreviated "DA."
As a member of the catecholamine family, dopamine is a precursor to epinephrine (adrenaline) and norepinephrine (noradrenaline) in the biosynthetic pathways for these neurotransmitters. Arvid Carlsson won a share of the 2000 Nobel Prize in Physiology or Medicine for showing that dopamine is not just a precursor to these, but a neurotransmitter as well.
Dopamine is synthesized in the body (mainly by nervous tissue and adrenal glands) by the decarboxylation of DOPA by aromatic-L-amino-acid decarboxylase. In neurons, dopamine is packaged after synthesis into vesicles, which are then released in response to the presynaptic action potential. The inactivation mechanism of neurotransmission are 1) uptake via a specific transporter; 2) enzymatic breakdown; and 3) diffusion. Uptake back to the presynaptic neuron via the dopamine transporter is the major role in the inactivation of dopamine neurotransmission. The recycled dopamine will face either breakdown by an enzyme or be re-packaged into vesicles and reused.
Functions of Dopamine in the Brain
Role in Movement
Dopamine is critical to the way the brain controls our movements and is a crucial part of the basal ganglia motor loop. Shortage of dopamine, particularly the death of dopamine neurons in the nigrostriatal pathway, causes Parkinson's disease, in which a person loses the ability to execute smooth, controlled movements.
Role in Cognition and Frontal Cortex Function
In the frontal lobes, dopamine controls the flow of information from other areas of the brain. Dopamine disorders in this region of the brain can cause a decline in neurocognitive functions, especially memory, attention and problem-solving.
Role in Pleasure and Motivation
Dopamine is commonly associated with the pleasure system of the brain, providing feelings of enjoyment and reinforcement to motivate us to do, or continue doing, certain activities. Dopamine is released (particularly in areas such as the nucleus accumbens and striatum) by naturally-rewarding experiences such as food, sex, use of certain drugs and neutral stimuli that become associated with them. This theory is often discussed in terms of drugs (such as cocaine and amphetamines), which seem to be directly or indirectly related to the increase of dopamine in these areas, and in relation to neurobiological theories of addiction, which argue that these dopamine pathways are pathologically altered in addicted persons. The mechanisms of cocaine and amphetamine are different, however. Cocaine acts as a dopamine transporter blocker, competively inhibiting dopamine uptake to increase the lifetime of dopamine. On the other hand, amphetamines act as dopamine transporter substrates to competitively inhibit dopamine uptake and increase the dopamine efflux via a dopamine transporter.
However, the idea that dopamine is the 'reward chemical' of the brain, a view held by many during early stages of its research, seems too simple as more evidence has been gathered. Dopamine is known to be released when unpleasant or aversive stimuli are encountered, suggesting that it is not only associated with 'rewards' or pleasure. Recent research has begun to examine whether or not the firing of dopamine neurons might function as a reward-prediction error signal, based on evidence that, when a reward is greater than expected, there is an increase in the firing of certain dopaminergic neurons (in contrast to when there is a lesser-than-expected reward, and there is a marked decrease in the firing of the same neurons). Some argue that dopamine may be involved in desire rather than pleasure. Drugs that are known to reduce dopamine activity (e.g., antipsychotics) have been shown to reduce people's desire for pleasurable stimuli, despite the fact that they will rate them as just as pleasurable when they actually encounter or consume them. It seems that these drugs reduce the wanting but not the liking, providing more evidence for the desire theory.
Other theories suggest that the crucial role of dopamine may be in predicting pleasurable activity. Related theories argue that dopamine function may be involved in the salience ('noticeableness') of perceived objects and events, with potentially important stimuli (including rewarding things, but also things that may be dangerous or a threat) appearing more noticeable or more important. This theory argues that dopamine's role is to assist decision-making by influencing the priority of such stimuli to the person concerned.
However, the above theories are based on correlational, rather than causal, experimental evidence. The available experimental evidence that examined causal rather than correlational relationships between dopamine and motivation does not seem to agree with any of above-stated theories. For example, pharmacological blockade of brain dopamine receptors increases rather than decreases the rate of drug-taking behavior. The theories viewing dopamine as the mediator of 'desire/wanting,' 'predicting pleasurable activity,' 'noticeableness' or 'decision-making' cannot adequately explain this experimental evidence. Thus, the functional role of dopamine in motivation remains to be the topic of controversy.
Deficits in dopamine levels have also been implicated as one of a possible array of causes for Attention deficit disorder, and some types of medications used to treat ADD and ADHD will help to stimulate dopaminergic systems, leading to potentially heightened, but preferably not distorted, sensation, for those who may be afflicted by it and be receiving treatment for it.
Dopamine and psychosis
Disruption to the dopamine system has also been strongly linked to psychosis and schizophrenia. Dopamine neurons in the mesolimbic pathway are particularly associated with these conditions. This is partly due to the discovery of a class of drugs called the phenothiazines (which block D2 dopamine receptors) that can reduce psychotic symptoms, and partly due to the finding that drugs such as amphetamine and cocaine (which are known to greatly increase dopamine levels) can cause psychosis. Because of this, most modern antipsychotic medication is designed to block dopamine function to varying degrees. Blocking the D2 dopamine receptor is known to cause relapse in patients that have achieved remission from depression, and such blocking also counteracts the effectiveness of SSRI medication.
See the article on the dopamine hypothesis of psychosis for a wider discussion of this topic.
Therapeutic use
Levodopa is a dopamine precursor used to treat Parkinson's disease. It is typically co-administered with an inhibitor of peripheral catechol-O-methyl transferase, such as carbidopa (co-careldopa) or benserazide (co-beneldopa).
Dopamine is also used as an inotropic drug in patients with shock to increase cardiac output and blood pressure.
Major Dopamine Pathways
- Mesocortical pathway
- Mesolimbic pathway
- Nigrostriatal pathway
- Tuberoinfundibular pathway
See also
- Addiction
- Amphetamine
- Antipsychotic
- Catecholamine
- Catechol-O-methyl transferase
- Cocaine
- Dopamine hypothesis of schizophrenia
- Methylphenidate
- Neurotransmitter
- Parkinson's disease
- Schizophrenia
External links
Category:Catecholamines
Category:Neurotransmitters
Category:Phenethylamines
ja:ドパミン
th:โดพามีน
Brain
In the anatomy of animals, the brain, or encephalon (Greek for "in the head"), is the higher, supervisory center of the nervous system. The term 'brain' is typically used in connection with vertebrate nervous systems, and less often with regard to the nervous system of invertebrates. In the latter, neural control is performed by collections of ganglia. The brain is an extremely complex organ: the human brain is a collection of 100 billion neurons, each linked with up to 25,000 others. This huge number of interconnecting neurons, often referred to as a neural ensemble, is what makes the brain intelligent—enabling humans to analyze sensory signals, control the body, and think. In most animals, the brain is located in the head, close to the primary sensory apparatus and the mouth.
Hippocrates considered the brain to be the seat of thought, while Aristotle believed it to be a cooling system for the blood. Today the study of the mind and brain consists of Neuroscience, the field of biology that studies the brain at its various levels of organization (from single neurons to functional systems such as visual system, auditory system, motor system and others); and psychology, the study of the cognition that arises from the neural function of the brain. Attempts have also been made to directly "read" the brain, which has been accomplished in a rudimentary manner through a brain-computer interface. In recent years, several institutions and bodies have undertaken research on recreating the neural structure of the brain with aim to produce human-like cognition and intelligence in computers.
The brain controls and coordinates most movement, behavior and homeostatic body functions (such as heartbeat, blood pressure, fluid balance and body temperature). The brain is responsible for cognition, emotion, memory, motor learning and other kinds of learning. However, many behaviors, such as simple reflexes and basic locomotion, can be executed under spinal cord control alone.
The importance of the brain
The brain in animals
Three groups of animals, with some exceptions, have notably complex brains: the arthropods (insects and crustaceans), the cephalopods (octopuses, squid, and similar mollusks), and the craniates (vertebrates and their cousins). The brain of arthropods and cephalopods arises from twin parallel nerve cords that extend through the body of the animal. In arthropod, the brain consists of a central brain with three divisions and large optical lobes behind each eye for visual processing.
eye
The brain of craniates develops from the anterior section of a single dorsal nerve cord, which later becomes the spinal cord. In craniates, the brain is protected by the bones of the skull. In vertebrates, increasing complexity in the cerebral cortex correlates with height on the phylogenetic and evolutionary tree. Primitive vertebrates, like fish, reptiles, and amphibians have cortices with fewer than six layers of neurons, a structure known as allocortex (also named heterotypic cortex) (Martin, 1996). More complex vertebrates such as mammals have developed a six-layered neocortex (other terms: homotypic cortex, neocortex, neopallium), in addition to having some parts of the brain that are allocortex (Martin, 1996). In mammals, increasing convolutions of the brain, called gyri, are characteristic of animals with more advanced brains. These convolutions evolved to provide a larger surface area for a greater number of neurons, while keeping the volume of the brain compact enough to fit inside the skull.
The human brain
The structure of the human brain is different from that of other animals in several significant ways. These differences have allowed for many abilities over and above those of other animals, such as advanced cognitive skills. Human encephalization is especially pronounced in the neocortex, the most complex part of the cerebral cortex. The proportion of the human brain that is devoted to the neocortex—and the most advanced part within it, the prefrontal cortex—is larger than in all other animals.
Humans enjoy unique neural capacities, but much of the human neuroarchitecture is shared with ancient species. Basic systems that alert the nervous system to stimulus, that sense events in the environment, and that monitor the condition of the body are similar to those of the most basic vertebrates. The neural circuitry underlying human consciousness includes both the advanced neocortex and protypical structures of the brain stem. The human brain also has a a million billion synaptic connections, making it one of the most densely connected network systems in the known universe; however, more complex structures may exist.
Pathology of the brain
The loss of function in the brain fulfills some definitions of death. Injuries to the brain tend to affect large areas of the organ, sometimes causing major deficits in intelligence, memory and control of the body. Head trauma, caused, for example, by vehicle and industrial accidents, is a leading cause of death in youth and middle age. In these cases, more damage is typically caused by resultant swelling (edema) than by the impact itself. Stroke, caused by the blockage of blood vessels in the brain, is another major cause of death from brain damage.
Other problems in the brain can be more accurately classified as diseases rather than injuries. Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, motor neurone disease, and Huntington's disease, are caused by the gradual death of individual neurons, leading to decrements in movement control, memory, and cognition. Currently, only the symptoms of these diseases can be treated, but stem cell research may offer a cure. Mental illness, such as clinical depression, schizophrenia, bipolar disorder, and post-traumatic stress disorder, are brain diseases that impact on the personality and typically on other aspects of mental and somatic function. These disorders may be treated by psychiatric therapy, by pharmaceutical intervention, or by a combination of treatments; therapeutic effectiveness varies significantly among individuals.
pharmaceutical
Some infectious diseases affecting the brain are caused by viral and bacterial infection(s). Infection of the meninges, the membrane that covers the brain, can lead to meningitis. Bovine spongiform encephalopathy (also known as mad cow disease), is deadly in cattle and is linked to prions. Kuru is a similar prion-borne degenerative brain disease affecting humans. Both are linked to the ingestion of neural tissue, and may be an evolutionary defense against cannibalism. Viral or bacterial causes have been substantiated in multiple sclerosis, Parkinson's disease, Lyme disease, encephalopathy and encephalomyelitis.
Some brain disorders are congenital. Tay-Sachs disease, Fragile X syndrome, Down syndrome, and Tourette syndrome are all linked to genetic and chromosomal errors. Malfunctions in the embryonic development of the brain can be caused by genetic factors, by drug use, and disease during a mother's pregnancy.
Other matters
Some philosophers consider that "brain" is synonymous with "mind", while others (such as strong AI theorists) believe that the mind is analogous to software and the brain to hardware. This issue—related to the mind-body problem—and many other issues, are the subjects of the area of the philosophy of mind. Questions asked in this field typically relate to the nature of consciousness and whether non-human animals are conscious beings.
Computer scientists have produced computer systems called neural networks, loosely based on the structure of neuron connections in the brain. Artificial intelligence seeks to replicate brain function—although not necessarily brain mechanisms—but as yet is an immature science. Creating algorithms to mimic a biological brain is extremely difficult because the brain is not a static arrangement of circuits, but a network of vastly interconnected neurons that are constantly changing their connectivity and sensitivity. More recent work in both neuroscience and artificial intelligence models the brain using the mathematical tools of chaos theory and dynamical systems.
Brain activity can be detected by electrodes, raising the possibility of "brain-computer interface". The reverse path has been demonstrated: brain implants have been used to generate artificial hearing and (crude and experimental) artificial vision for deaf and blind people; brain pacemakers are now commonly used to regulate brain activity in conditions such as Parkinson's disease.
Both of these avenues of research are confronted with potentially serious ethical implications. For example, by placing electrodes in the brain and using a remote control, researchers have been able to remotely control the movements of a rat, combining commands of what to do with the stimulation of the brain pleasure centers. This raises the possibility of creating an electronically controlled biological "ratbot" that could be used in dangerous circumstances.
The biology of the brain
Despite the variance of the species in which the brain is found there are many common features in its cellular make-up, its structure and its function. On a cellular level, the brain is composed of two classes of cell, neurons and glia, both of which contain several different cell types which perform different functions. Interconnected neurons form neural networks (or neural ensembles). These networks are similar to man-made electrical circuits in that they contain circuit elements (neurons) connected by biological wires (nerve fibers). Of course, these do not form simple one-to-one electrical circuits (as is the case in many man-made circuits), neurons typically connect to at least a thousand other neurons. These highly specialized circuits make up systems which are the basis of perception, action and higher cognitive function.
The brain contains anatomical and functional divides. In mammals, the most obvious partitioning of the brain is into the cerebrum (Latin for "brain", a large, anterior part that consists of two convoluted hemispheres and deep nuclei), cerebellum (Latin for "small brain", a smaller, structure behind the cerebrum with two rippled hemispheres and deep cerebellar nuclei), and brain stem (an elongated structure connecting the brain to the spinal cord). These parts are further divided into hemispheres, lobes, gyri, cortices, cytoarchitectonic and functional areas, nuclei, layers, fiber tracks and so forth.
In summary, the chemical and electrical impulses continually passing through the cells of the brain produce all control, action and cognitive function in the body.
Histology
lobe
Neurons, the cells that generate action potentials and convey them to other cells, constitute the chief class of brain cells. In each particular brain area, input (or afferent) neurons, output (or efferent) neurons and interneurons are typically found. Input neurons are recipients of projections from other brain areas. Output neurons project to the other areas. Interneurons are the neurons which do not leave the area. In addition to neurons, the brain contains glial cells in the proportion roughly 10 glial cells to every neuron; these are traditionally seen to perform supportive roles to neurons and fill out the space between them (hence its name, Greek for 'glue'). Most types of glia in the brain (and the rest of the central nervous system) are present in the entire nervous system, exceptions include oligodendrocytes which insulate neural axons (a role performed by Schwann cells in the peripheral nervous system). Oligosaccharides are the defining factor between white matter and grey matter in the brain—white matter is composed of myelinated (insulated) axons, whereas grey matter contains mostly cell soma, dendrites and unmyelinated portions of axons and glia and a smaller proportion of myelinated axons.
In mammals, the brain also contains a certain amount of connective tissue called the meninges which is a system of membranes that separate the skull from the brain. The three-layered covering is made of, from the outside in, dura mater, arachnoid and pia mater (the latter two are connected and thus often considered as a single layer, the pia-arachnoid). Below the arachnoid is the subarachnoid space which contains cerebrospinal fluid which protects the nervous system. Blood vessels enter the central nervous system through the perivascular space above the pia mater. A blood-brain barrier protects the brain from unwanted substances that might enter it through the blood.
The brain is suspended in cerebrospinal fluid, which circulates between layers of the meninges and through cavities in the brain called ventricles. It is important both chemically (metabolism) and mechanically (shock-prevention).
Anatomy
Although the
histology of the brain is common to all those who have one, the structural anatomy is not. Apart from the general nature of the brain to order into lobes and suchforth, the lobes into which it has evolved are not common across the vertebrate/invertebrate divide. There are further dissimilarities within invertebrates, though vertebrates tend to share certain commonalities.
Invertebrates
In insects, the brain can be divided into four parts, the optical lobes, the protocerebrum, the deutocerebrum, and the tritocerebrum. The optical lobes are positioned behind each eye and process visual stimuli (Butler, 2000). The protocerebrum contains the mushroom bodies, which respond to smell, and the central body complex. The deutocerebrum includes the antennal lobes, which are similar to the mammalian olfactory bulb, and the mechanosensory neuropils which receive information from touch receptors on the head and antennae. The antennal lobes of flies and moths are quite complex.
In cephalopods, the brain is divided into two regions: the supraesophageal mass and the subesophageal mass. These parts are divided by the animal's esophagus. The supra- and subesophageal masses are connected to each other on either side of the esophagus by the basal lobes and the dorsal magnocellular lobes. The large optic lobes are sometimes not considered to be part of the brain proper since the optic lobes anatomically separate from the brain and are joined to the brain by the optic stalks. However, the optic lobes perform much of the visual processing and can be functionally considered to be a part of the brain.
Vertebrates
In vertebrates, a gross division into three major parts is used: hindbrain (medulla oblongata and metencephalon), midbrain (mesencephalon) and forebrain (diencephalon and telencephalon). Varied taxonomies have been used by assorted schools at various times in history for the study of diverse species.
An anterior part of the telencephalon called the cerebrum makes up the largest section of the mammalian brain and in humans, its surface has many deep fissures (sulci) and convolutions (gyri), giving a wrinkled appearance to the brain. In most vertebrates the metencephalon is the highest integration center in the brain, whereas in mammals this role has been adopted by the cerebrum. Behind (or in humans, below) the cerebrum is the cerebellum, a convoluted structure whose neural circuitry is often compared with crystal structure. Cerebellum participates in the control of movement. The cerebellum attaches to the hindbrain in a structure called the pons. The cerebrum and the cerebellum consist each of two halves (hemispheres). The corpus callosum connects the two hemispheres of the cerebrum. An outgrowth of the telencephalon called the olfactory bulb is a major structure in many animals, but in humans and other primates, it is relatively small.
Vertebrate nervous systems are distinguished by encephalization and bilateral symmetry. Encephalization refers to the tendency for more complex organisms to gain a larger-size brains through evolutionary time. Larger vertebrates develop a complex of layered, networked and convoluted grey matter and white matter. Grey matter refers to tissue mostly comprised of neurons and can be found on the surface of cerebral cortex, as well as in clusters called nuclei deep within the brain. White matter refers to axons and their surrounding myelin insulation, which gives this tissue its white color. White matter is found in bundles of fibers known as tracts which connect the different parts of the brain. In modern species most closely related to the first vertebrates, brains are covered with gray matter that has a three-layer structure. Their brains also contain deep brain nucleus and fiber tracks forming the white matter. Most regions of the human cerebral cortex have six layers of neurons, a structure known as neocortex.
Brain Regions in Vertebrates
According to the hierarchy based on embryonic and evolutionary development, chordate brains are composed of the following regions:
- RHOMBENCEPHALON (Greek for "rhomboid brain")
- Myelencephalon (Greek for "brain marrow", also called medulla oblongata which means "long marrow" in Latin)
- Metencephalon (Greek for "after the brain"; also called hindbrain)
- pons
- cerebellum
- MESENCEPHALON (Greek for "middle brain", also called midbrain)
- tectum
- midbrain tegmentum
- substantia nigra
- crus cerebri (also called cerebral peduncles and pedunculus cerebri)
- PROSENCEPHALON
- Diencephalon (Greek for "brain in between")
- thalamus
- hypothalamus (Greek for "under the thalamus")
- pituitary gland
- epithalamus
- pineal gland
- Telencephalon (Greek for "end brain", i.e. the most rostral part of the brain; also called forebrain)
- TELENCEPHALON NUCLEI
- putamen
- caudate nucleus
- putamen
- globus pallidus
- amygdala
- CEREBRAL CORTEX
- Archipallium (Greek for "first cloak", i.e. cortex that developed first; also called archeocortex)
- hippocampus
- Paleopallium (Greek for "ancient cloak"; also called "paleocortex")
- priform(olfactory) cortex
- parahippocampal gyrus
- Neopallium (Greek for "new cloak"; also called "paleocortex"; also called neocortex and isocortex)
- frontal lobe
- temporal lobe
- parietal lobe
- occipital lobe
- insula
- cingulate cortex
In addition, the brain is often subdivided into the following major parts:
- BRAINSTEM
- Medulla
- Pons
- Midbrain
- CEREBELLUM
- Cerebellar cortex
- Cerebellar nuclei
- BASAL GANGLIA (some midbrain nuclei, such as substantia nigra are usually considered as basal ganglia)
- Striatum (caudate nucleus and putamen)
- Globus pallidus
- HIPPOCAMPUS
- AMYGDALA
- THALAMUS
- HYPOTHALAMUS
- CEREBRAL CORTEX
Yet alternative classifications arrange brain areas into functional systems:
- Limbic system
- Sensory systems
- Visual system
- Olfactory system
- Gustatory system
- Auditory system
- Somatosensory system
- Motor system
- Associative areas
Function
Associative areas
Vertebrate brains receive signals through nerves arriving from the sensors of the organism, interpret those signals and formulate reactions based on built-in programs and learned experiences. A similarly extensive nerve network delivers signals from a brain to control muscles throughout a body. Anatomically, the majority of afferent and efferent nerves (with the exception of cranial nerves) are connected to the spinal cord, which then transfers the signals to the brain.
Sensory input is processed by the brain to recognize danger, find food, identify potential mates and perform more sophisticated functions. Visual, touch, and auditory sensory pathways of vertebrates are routed to specific nuclei of the thalamus and then to regions of the cerebral cortex that are specific to each sensory system: the visual system, the auditory system and the somatosensory system. Olfactory pathways are routed to the olfactory bulb, then to various parts of the olfactory system. Taste is routed through the brainstem and then to other portions of the gustatory system.
To control movement, the brain has several parallel systems of muscle control. The motor system controls voluntary muscle movement, aided by motor areas of the cerebral cortex, the cerebellum and the basal ganglia — the system that eventually projects to the spinal cord. Nuclei in the brainstem control many involuntary muscle functions such as heartrate and breathing. In addition, many automatic acts (simple reflexes, locomotion) can be controlled by the spinal cord alone.
Brains also produce hormones that can influence organs and glands elsewhere in a body - conversely, brains also react to hormones produced elsewhere in the body. In mammals, most of these hormones are released into the circulatory system by a structure called the pituitary gland.
It is hypothesized that developed brains derive consciousness from interaction among numerous systems within the brain. Cognitive processing in mammals occurs in the cerebral cortex but relies on mid-brain and limbic functions as well, especially those of the thalamus and hippocampus. Among "younger" (in an evolutionary sense) vertebrates, advanced processing involves progressively rostral (forward) regions of the brain.
Hormones, incoming sensory information, and cognitive processing performed by the brain determine the brain state. Stimulus from any source can trigger a general arousal process that focuses cortical operations to processing of the new information. Cognitive priorities are constantly shifted by a variety of factors, such as hunger, fatigue, beliefs, unfamiliar information or threats. The simplest dichotomy related to processing of threats is the fight-or-flight response mediated by the amygdala, among other structures.
The study of the brain
Fields of study
Several areas of science specifically study the brain. Neuroscience seeks to understand the nervous system, including the brain, from a biological perspective. Psychology seeks to understand behavior and the brain. The terms neurology and psychiatry usually refer to medical applications of neuroscience and psychology, respectively. Cognitive science seeks to unify neuroscience and psychology with other fields that concern themselves with the brain, such as | | |
