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{{BioPsy}}
  
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! style="background: #fff" colspan="2" | [[Image:MPTP.png|center|160px]]
  
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|IUPACName=1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
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''MPTP''
  
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! colspan="2" | [[IUPAC nomenclature|IUPAC]] name:
  
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| CASNo=28289-54-5
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1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
  
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| PubChem=1388
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| ChemSpiderID = 1346
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| style="background: #eee" | '''[[CAS number]]'''
  
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| EINECS=248-939-7
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| style="background: #def" | 28289-54-5
  
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| SMILES=CN1CCC(=CC1)C2=CC=CC=C2
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| MeSHName = 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
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| style="background: #def" | 248-939-7
  
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| Formula=C<sub>12</sub>H<sub>15</sub>N
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| style="background: #eee" | [[Chemical formula]]
  
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| MolarMass=173.25 g/mol
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| style="background: #def" | [[Carbon|C]]<sub>12</sub>[[Hydrogen|H]]<sub>15</sub>[[Nitrogen|N]]
  
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| style="background: #def" | 173.2542 g/mol
  
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| style="background: #def" | Schedule II as [[Meperidine]] analog ([[USA]])
  
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'''MPTP''' (1-[[methyl]]-4-[[phenyl]]-1,2,3,6-tetrahydro[[pyridine]]) is a [[neurotoxin]] that causes permanent symptoms of [[Parkinson's disease]] by killing certain [[neuron]]s in the [[substantia nigra]] of the [[brain]]. It is used to study the disease in monkeys.
   
−
'''MPTP''' (1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine) is a [[chemical]] that is related to the [[opioid]] [[analgesic]] [[recreational drug use|drugs]]. MPTP itself does not have any opioid effect, but it may be produced accidentally during illicit manufacture of [[MPPP]], a synthetic [[opioid]] with effects similar to those of [[heroin]] and [[morphine]].
 +
While MPTP itself does not have [[opioid]] effects, it is related to [[MPPP]], a synthetic opioid [[recreational drug use|drug]] with effects similar to those of [[heroin]] and [[morphine]]. MPTP can be accidentally produced during the illicit manufacture of MPPP, and that is how its Parkinson-inducing effects were first discovered.
  +
  +
==Toxicity==
  +
Injection of MPTP causes rapid onset of [[Parkinsonism]], hence users of MPPP contaminated with MPTP will develop these symptoms.
   
−
MPTP causes [[Parkinson's disease|Parkinsonian]] [[adverse effect (medical)|side-effect]]s, hence some users of MPPP develop these symptoms. This happens when MPTP is metabolized into [[MPP+]] (by [[MAO-B]]), which kills [[neurons]] in a part of the brain called the [[substantia nigra]]. MPP+ interferes with [[complex I]] of the [[electron transport chain]], a component of mitochondrial metabolism, which leads to cell death and causes the buildup of free radicals, toxic molecules that contribute further to cell destruction.
 +
MPTP itself is not toxic, and as a [[lipophilicity|lipophilic]] compound can cross the [[blood-brain barrier]]. Once inside the brain, MPTP is metabolized into the toxic [[cation]] 1-methyl-4-phenylpyridinium ([[MPP+]]) by the enzyme [[MAO-B]] of [[glial cell]]s. MPP+ primarily kills [[dopaminergic|dopamine-producing]] [[neurons]] in a part of the brain called the pars compacta of the [[substantia nigra]]. MPP+ interferes with [[complex I]] of the [[electron transport chain]], a component of [[mitochondria]]l metabolism, which leads to cell death and causes the buildup of [[free radical]]s, toxic molecules that contribute further to cell destruction.
   
  +
Because MPTP itself is not directly harmful, toxic effects of acute MPTP poisoning can be mitigated by the administration of [[MAOI|monoamine oxidase inhibitors]] (MAOIs) such as [[selegiline]]. MAOIs prevent the metabolism of MPTP to MPP+ by inhibiting the action of MAO-B, minimizing toxicity and preventing neural death.
⚫
MPTP has quite selective abilities to effect neuronal death in dopaminergic cells, apparently through a high-affinity uptake process in nerve terminals normally used to reuptake dopamine after it has been released into the synaptic cleft. Such effects lead to gross depletion of dopaminergic neurons which has severe implications on cortical control of complex movements.The direction of complex movement is based from the substantia nigra to the putamen and caudate nucleus which then relay signals to the rest of the brain. This pathway is controlled via dopamine-using neurons, which MPTP selectively destroys, resulting over time in parkinsonism.
  
   
  +
MPTP has quite selective abilities to cause neuronal death in dopaminergic cells, apparently through a high-affinity uptake process in nerve terminals normally used to reuptake dopamine after it has been released into the [[chemical synapse|synaptic cleft]]. The [[dopamine transporter]] moves MPP+ inside the cell.
−
The neurotoxicity of MPTP was discovered in 1976 after Barry Kidston, a 23-year-old chemistry graduate student in [[Maryland]], synthesized MPPP incorrectly and injected the result. It was contaminated with MPTP, and within three days he began exhibiting symptoms of Parkinson's disease. The [[National Institute of Mental Health]] found traces of MPTP in his lab and eventually discovered its effects by testing the chemical on rats.
  
   
  ⚫
The resulting gross depletion of dopaminergic neurons has severe implications on [[cerebral cortex|cortical]] control of complex movements. The direction of complex movement is based from the substantia nigra to the [[putamen]] and [[caudate nucleus]] which then relay signals to the rest of the brain. This pathway is controlled via dopamine-using neurons, which MPTP selectively destroys, resulting over time in parkinsonism.
−
In 1982, seven people in Santa Clara County, California were diagnosed with Parkinson's after using MPPP contaminated with MPTP. [[William Langston|J. William Langston]], then a neurologist at [[Santa Clara Valley Medical Center]] and faculty member at Stanford Medical School, tracked down MPTP as the cause, researched its effects on primates, and was eventually able to successfully treat motor symptoms of three of the seven patients with neural grafts of fetal [[stem cell]]s from aborted human fetuses in collaboration with neuroscientists from [[Lund University|Lund University Hospital]] in Sweden. This experience was documented in a book he authored, ''The Case of the Frozen Addict'' (ISBN 0-679-42465-2), about his quest for a cure, which was later featured in two NOVA productions by Public Broadcasting Service.
  
  +
  +
MPTP causes parkinsonism in [[primate]]s including humans. [[Rodent]]s are much less susceptible. Rats are almost immune to the adverse effects of MPTP. Mice suffer from cell death in the substantia nigra (to differing degree according to the strain of mice used) but do not show parkinsonian symptoms. It is believed that the lower levels of MAO B in the rodent brain's capillaries may be responsible for this.<ref>J. William Langston. The Impact of MPTP on Parkinson's Disease Research: Past, Present, and Future. In: ''Parkinson's Disease. Diagnosis and Clinical Management'' by Stewart A. Factor and William J. Weiner (eds.), Demos Medical Publishing, 2002. [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=parkinsons Searchable online version]</ref>
  +
  +
==Discovery in users of illicit drugs==
  +
The neurotoxicity of MPTP was hinted at in 1976 after Barry Kidston, a 23-year-old chemistry graduate student in [[Maryland]], synthesized MPPP incorrectly and injected the result. It was contaminated with MPTP, and within three days he began exhibiting symptoms of Parkinson's disease. The [[National Institute of Mental Health]] found traces of MPTP and other [[meperidine]] analogues in his lab. They tested the substances on rats, but due to rodents' tolerance for this type of neurotoxin nothing was observed. Kidston's parkinsonism was successfully treated with [[levodopa|Levo-dopa]] but he died 18 months later from a [[cocaine]] overdose. Upon autopsy, destruction of dopamine-neurons in the substantia nigra was discovered.<ref>Fahn, Stanley. The Case of the Frozen Addicts: How the Solution of an Extraordinary Medical Mystery Spawned a Revolution in the Understanding and Treatment of Parkinson's Disease. ''The New England Journal of Medicine''. Dec 26, 1996. Vol. 335, Iss. 26; pg. 2002</ref>
  +
  +
In 1982, seven people in [[Santa Clara County, California]] were diagnosed with Parkinsonism after having used MPPP contaminated with MPTP. The neurologist [[William Langston|J. William Langston]] in collaboration with NIH tracked down MPTP as the cause, and its effects on primates were researched. Eventually the motor symptoms of two of the seven patients were successfully treated at [[Lund University|Lund University Hospital]] in [[Sweden]] with neural grafts of [[stem cell]]s from [[abortion|aborted]] human [[fetus]]es.<ref>[http://query.nytimes.com/gst/fullpage.html?res=9E0CE7D91030F935A15752C1A964958260 Success reported using fetal tissue to repair a brain], ''[[The New York Times]]'', 26 November 1992</ref>
  +
  +
Langston documented the case in his 1995 book ''The Case of the Frozen Addicts'' (ISBN 0-679-42465-2), which was later featured in two [[NOVA (TV series)|NOVA]] productions by [[Public Broadcasting Service|PBS]].
   
 
== Contribution of MPTP to research into Parkinson's disease ==
  
== Contribution of MPTP to research into Parkinson's disease ==
  ⚫
Langston ''et al.''(1984)
  ⚫
found that injections of MPTP in [[squirrel monkey]]s resulted in parkinsonism, symptoms of which were subsequently reduced by [[levodopa|Levo-dopa]], a precursor for the neurotransmitter dopamine, currently the drug-of-choice in treatment of Parkinson's. The symptoms and brain structures of MPTP-induced Parkinson's are fairly indistinguishable to the point that MPTP may be used to simulate the disease in order to study Parkinson's physiology and possible treatments within the laboratory. Mouse studies have shown that susceptibility to MPTP increases with age.
   
  +
Knowledge of MPTP and its use in reliably recreating Parkinson's disease in experimental models has inspired scientists to investigate the possibilities of surgically replacing neuron loss through fetal tissue implants, [[subthalamus|subthalamic]] [[deep brain stimulation|electrical stimulation]] and [[stem cell]] research[http://www.wired.com/medtech/drugs/news/2007/09/parkinsons_prisoner2], all of which have demonstrated initial, provisional successes.
⚫
Langston et al.(1984)
 
⚫
found that, injections of MPTP in squirrel monkeys resulted in parkinsonism, symptoms of which were subsequently reduced by Levo-dopa, a precursor for the neurotransmitter dopamine, currently the drug-of-choice in treatment of Parkinson's. The symptoms and brain structures of MPTP-induced Parkinson's are fairly indistinguishable to the point that MPTP may be used to simulate the disease in order that science may study Parkinson's physiology and possible treatments within the laboratory.
  
   
−
Based on this, it has been postulated that [[Parkinson's disease]] may be caused by minute amounts of MPP+ like compounds from ingestion or exogenously through repeated exposure and that these substances are too minute to be detected significantly by epidemiological studies.[http://www.silsoe.cranfield.ac.uk/ieh/pdf/w21.pdf] Nevertheless, knowledge of MPTP and its use in reliably recreating Parkinson's disease in experimental models has inspired scientists to investigate the possibilities of surgically replacing neuron loss through fetal tissue implants, subthalamic electrical stimulation and stem cell research{{Fact|date=February 2007}}, all of which have demonstrated initial, provisional successes.
 +
It has been postulated that Parkinson's disease may be caused by minute amounts of MPP+ like compounds from ingestion or exogenously through repeated exposure and that these substances are too minute to be detected significantly by epidemiological studies.<ref>[http://www.silsoe.cranfield.ac.uk/ieh/pdf/w21.pdf Pesticides and Parkinson's Disease - A critical review]. Institute of Environment and Health, [[Cranfield University]], October 2005.</ref>
  +
−
{{Fact|date=February 2007}}
  
  +
In 2000 another animal model for Parkinson's Disease was found. It was shown that the [[pesticide]] and [[insecticide]] [[rotenone]] causes parkinsonism in rats by killing dopaminergic neurons in the substantia nigra. Like MPP+, rotenone also interferes with [[complex I]] of the [[electron transport chain]].<ref>[http://www.ninds.nih.gov/funding/research/parkinsonsweb/greenamyre_summary.htm Summary of the article by Dr. Greenamyre on pesticides and Parkinson's Disease], National Institute of Neurological Disorders and Stroke, 9 February 2005</ref>
  +
  +
==Synthesis and uses==
  +
MPTP was first synthesized as an [[analgesic]] in 1947 by Ziering ''et al.'' It can be formed by mixing [[formaldehyde]], [[methylamine]] and alpha-[[methylstyrene]].
  +
It was tested as a treatment for various conditions, but the tests were halted when Parkinson-like symptoms were noticed in monkeys. In one test of the substance, two of six human subjects died.<ref name=vinken/>
   
 
== See also ==
  
== See also ==
  +
* [[Dopamine]]
 
* [[MPPP]]
  
* [[MPPP]]
  +
  +
==References==
  +
<references/>
  +
  +
   
 
==External links==
  
==External links==
−
*[http://www.time.com/time/archive/preview/0,10987,1101850408-141542,00.html MPTP in California, 1982]
  
 
*[http://www.thepi.org/altruesite/php/section.php?id=10 History of The Parkinson's Institute dates back to 1982]
  
*[http://www.thepi.org/altruesite/php/section.php?id=10 History of The Parkinson's Institute dates back to 1982]
   
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{{ChemicalSources}}
  
   
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[[Category:opioids]]
  
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[[Category:Neurotoxins]]
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[[Category:Opiates]]
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[[Category:Pyridines]]
 
[[Category:Parkinson's disease]]
  
[[Category:Parkinson's disease]]
 
[[Category:Substantia nigra]]
  
[[Category:Substantia nigra]]
   
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Latest revision as of 22:45, 2 November 2010

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Template:Chembox EINECS
style="background: #F8EABA; text-align: center;" colspan="2" Methylphenyltetrahydropyridine
File:MPTP structure.png
IUPAC name
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
Identifiers
CAS number 28289-54-5
PubChem 1388
MeSH 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine
SMILES CN1CCC(=CC1)C2=CC=CC=C2
Properties
Molecular formula C12H15N
Molar mass 173.25 g/mol
Hazards
style="background: #F8EABA; text-align: center;" colspan="2" Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references


MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is a neurotoxin that causes permanent symptoms of Parkinson's disease by killing certain neurons in the substantia nigra of the brain. It is used to study the disease in monkeys.

While MPTP itself does not have opioid effects, it is related to MPPP, a synthetic opioid drug with effects similar to those of heroin and morphine. MPTP can be accidentally produced during the illicit manufacture of MPPP, and that is how its Parkinson-inducing effects were first discovered.

Toxicity

Injection of MPTP causes rapid onset of Parkinsonism, hence users of MPPP contaminated with MPTP will develop these symptoms.

MPTP itself is not toxic, and as a lipophilic compound can cross the blood-brain barrier. Once inside the brain, MPTP is metabolized into the toxic cation 1-methyl-4-phenylpyridinium (MPP+) by the enzyme MAO-B of glial cells. MPP+ primarily kills dopamine-producing neurons in a part of the brain called the pars compacta of the substantia nigra. MPP+ interferes with complex I of the electron transport chain, a component of mitochondrial metabolism, which leads to cell death and causes the buildup of free radicals, toxic molecules that contribute further to cell destruction.

Because MPTP itself is not directly harmful, toxic effects of acute MPTP poisoning can be mitigated by the administration of monoamine oxidase inhibitors (MAOIs) such as selegiline. MAOIs prevent the metabolism of MPTP to MPP+ by inhibiting the action of MAO-B, minimizing toxicity and preventing neural death.

MPTP has quite selective abilities to cause neuronal death in dopaminergic cells, apparently through a high-affinity uptake process in nerve terminals normally used to reuptake dopamine after it has been released into the synaptic cleft. The dopamine transporter moves MPP+ inside the cell.

The resulting gross depletion of dopaminergic neurons has severe implications on cortical control of complex movements. The direction of complex movement is based from the substantia nigra to the putamen and caudate nucleus which then relay signals to the rest of the brain. This pathway is controlled via dopamine-using neurons, which MPTP selectively destroys, resulting over time in parkinsonism.

MPTP causes parkinsonism in primates including humans. Rodents are much less susceptible. Rats are almost immune to the adverse effects of MPTP. Mice suffer from cell death in the substantia nigra (to differing degree according to the strain of mice used) but do not show parkinsonian symptoms. It is believed that the lower levels of MAO B in the rodent brain's capillaries may be responsible for this.[1]

Discovery in users of illicit drugs

The neurotoxicity of MPTP was hinted at in 1976 after Barry Kidston, a 23-year-old chemistry graduate student in Maryland, synthesized MPPP incorrectly and injected the result. It was contaminated with MPTP, and within three days he began exhibiting symptoms of Parkinson's disease. The National Institute of Mental Health found traces of MPTP and other meperidine analogues in his lab. They tested the substances on rats, but due to rodents' tolerance for this type of neurotoxin nothing was observed. Kidston's parkinsonism was successfully treated with Levo-dopa but he died 18 months later from a cocaine overdose. Upon autopsy, destruction of dopamine-neurons in the substantia nigra was discovered.[2]

In 1982, seven people in Santa Clara County, California were diagnosed with Parkinsonism after having used MPPP contaminated with MPTP. The neurologist J. William Langston in collaboration with NIH tracked down MPTP as the cause, and its effects on primates were researched. Eventually the motor symptoms of two of the seven patients were successfully treated at Lund University Hospital in Sweden with neural grafts of stem cells from aborted human fetuses.[3]

Langston documented the case in his 1995 book The Case of the Frozen Addicts (ISBN 0-679-42465-2), which was later featured in two NOVA productions by PBS.

Contribution of MPTP to research into Parkinson's disease

Langston et al.(1984) found that injections of MPTP in squirrel monkeys resulted in parkinsonism, symptoms of which were subsequently reduced by Levo-dopa, a precursor for the neurotransmitter dopamine, currently the drug-of-choice in treatment of Parkinson's. The symptoms and brain structures of MPTP-induced Parkinson's are fairly indistinguishable to the point that MPTP may be used to simulate the disease in order to study Parkinson's physiology and possible treatments within the laboratory. Mouse studies have shown that susceptibility to MPTP increases with age.

Knowledge of MPTP and its use in reliably recreating Parkinson's disease in experimental models has inspired scientists to investigate the possibilities of surgically replacing neuron loss through fetal tissue implants, subthalamic electrical stimulation and stem cell research[1], all of which have demonstrated initial, provisional successes.

It has been postulated that Parkinson's disease may be caused by minute amounts of MPP+ like compounds from ingestion or exogenously through repeated exposure and that these substances are too minute to be detected significantly by epidemiological studies.[4]

In 2000 another animal model for Parkinson's Disease was found. It was shown that the pesticide and insecticide rotenone causes parkinsonism in rats by killing dopaminergic neurons in the substantia nigra. Like MPP+, rotenone also interferes with complex I of the electron transport chain.[5]

Synthesis and uses

MPTP was first synthesized as an analgesic in 1947 by Ziering et al. It can be formed by mixing formaldehyde, methylamine and alpha-methylstyrene. It was tested as a treatment for various conditions, but the tests were halted when Parkinson-like symptoms were noticed in monkeys. In one test of the substance, two of six human subjects died.[6]

See also

References

  1. ↑ J. William Langston. The Impact of MPTP on Parkinson's Disease Research: Past, Present, and Future. In: Parkinson's Disease. Diagnosis and Clinical Management by Stewart A. Factor and William J. Weiner (eds.), Demos Medical Publishing, 2002. Searchable online version
  2. ↑ Fahn, Stanley. The Case of the Frozen Addicts: How the Solution of an Extraordinary Medical Mystery Spawned a Revolution in the Understanding and Treatment of Parkinson's Disease. The New England Journal of Medicine. Dec 26, 1996. Vol. 335, Iss. 26; pg. 2002
  3. ↑ Success reported using fetal tissue to repair a brain, The New York Times, 26 November 1992
  4. ↑ Pesticides and Parkinson's Disease - A critical review. Institute of Environment and Health, Cranfield University, October 2005.
  5. ↑ Summary of the article by Dr. Greenamyre on pesticides and Parkinson's Disease, National Institute of Neurological Disorders and Stroke, 9 February 2005
  6. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named vinken


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