Carbidopa (sold as Lodosyn) is a drug given to people with Parkinson's disease in order to inhibit peripheral metabolism of levodopa. [edit] Pharmacology Carbidopa inhibits aromatic-L-amino-acid decarboxylase (DOPA Decarboxylase or DDC),[1] an enzyme important in the biosynthesis of L-tryptophan to serotonin and in the biosynthesis of L-DOPA to Dopamine (DA). Along with carbidopa, other DDC inhibitors are benserazide (Ro-4-4602), difluromethyldopa, and α-methyldopa. Used in tandem with L-DOPA (trade name levodopa, a dopamine precursor converted in the body to dopamine), it increases the plasma half-life of levodopa from 50 minutes to 1 1/2 hours. CarbiDOPA cannot cross the blood brain barrier, so it inhibits only peripheral DDC. It thus prevents the conversion of L-DOPA to dopamine peripherally. This reduces the side effects caused by dopamine on the periphery, as well as increasing the concentration of L-DOPA and dopamine in the brain. The combination of carbidopa/levodopa) carries the brand names of Sinemet, Parcopa and Atamet; whilst Stalevo is a combination with entacapone, which enhances the bioavailability of carbidopa and levodopa. Carbidopa is also used in combination with 5-HTP, a naturally occurring amino acid which is a precursor to the neurotransmitter serotonin and an intermediate in tryptophan metabolism. Carbidopa prevents 5-HTP's metabolism in the liver, which can lead to elevated levels of serotonin in the bloodstream. Research shows that co-administration of 5-HTP and carbidopa greatly increases plasma 5-HTP levels. Without the use of carbidopa, there is a significant risk of heart valve disease when taking 5-HTP, due to serotonin's affect on the heart.[2][3] In Europe, 5-HTP is prescribed with carbidopa to prevent the conversion of 5-HTP into serotonin until it reaches the brain.[4] [edit] References - ^ Gilbert JA, Frederick LM, Ames MM (November 2000). "The aromatic-L-amino acid decarboxylase inhibitor carbidopa is selectively cytotoxic to human pulmonary carcinoid and small cell lung carcinoma cells". Clinical cancer research : an official journal of the American Association for Cancer Research 6 (11): 4365–72. PMID 11106255. http://clincancerres.aacrjournals.org/cgi/pmidlookup?view=long&pmid=11106255.
- ^ Gustafsson BI, Tømmerås K, Nordrum I, Loennechen JP, Brunsvik A, Solligård E, Fossmark R, Bakke I, Syversen U, Waldum H (March 2005). "Long-term serotonin administration induces heart valve disease in rats". Circulation 111 (12): 1517–22. doi:10.1161/01.CIR.0000159356.42064.48. PMID 15781732.
- ^ Xu J, Jian B, Chu R, Lu Z, Li Q, Dunlop J, Rosenzweig-Lipson S, McGonigle P, Levy RJ, Liang B (December 2002). "Serotonin mechanisms in heart valve disease II: the 5-HT2 receptor and its signaling pathway in aortic valve interstitial cells". Am. J. Pathol. 161 (6): 2209–18. PMID 12466135. PMC 1850896. http://ajp.amjpathol.org/cgi/content/abstract/161/6/2209.
- ^ http://www3.interscience.wiley.com/journal/119498636/abstract?CRETRY=1&SRETRY=0
[edit] External links | Dopaminergics | | Receptor
Ligands | | | Benzazepines: 6-Br-APB • Fenoldopam • SKF-38,393 • SKF-77,434 • SKF-81,297 • SKF-82,958 • SKF-83,959; Ergot-derivatives: Bromocriptine • Cabergoline • Dihydroergocryptine • Lisuride • LSD • Pergolide; Dihydrexidine-derivatives: 2-OH-NPA • A-86,929 • Dihydrexidine • Dinapsoline • Dinoxyline • Doxanthrine; Morphine-derivatives: Apomorphine • Propylnorapomorphine; Piperazines: ABT-724 • Aripiprazole • Piribedil • WAY-100,635; Others: 7-OH-DPAT • 8-OH-PBZI • A-68,930 • A-77,636 • A-412,997 • ABT-670 • Amantadine • Aplindore • CY-208,243 • Memantine • PD-128,907 • PF-219,061 • Pramipexole • Pukateine • Quinpirole • RDS-127 • Rimantadine • Ropinirole • Rotigotine • SKF-89145 • SKF-89626 | | | | | | | Reuptake
Inhibitors | | | Releasing
Agents | Oxazolines: 4-Methylaminorex (4-MAR, 4-MAX) • Aminorex • Clominorex • Cyclazodone • Fenozolone • Fluminorex • Pemoline • Thozalinone; Phenethylamines (also Amphetamines, Cathinones, Phentermines, etc): 2-Hydroxyphenethylamine (2-OH-PEA) • 4-Methylamphetamine (4-MA) • 4-Methylmethamphetamine (4-MMA) • α-Ethylphenethylamine (α-Et-PEA) • Alfetamine • Amphetamine ( Dextroamphetamine, Levoamphetamine) • Amphetaminil • Amfepentorex • β-Methylphenethylamine (β-Me-PEA) • Benzodioxolylbutanamine (BDB) • Benzodioxolylhydroxybutanamine (BOH) • Benzphetamine • Buphedrone • Butylone • Cathine • Cathinone • Clobenzorex • Clortermine • Diethylcathinone (Diethylpropion, Amfepramone) • Dibutylone • Dimethoxyamphetamine (DMA) • Dimethoxymethamphetamine (DMMA) • Dimethylamphetamine • Dimethylcathinone (Dimethylpropion, Metamfepramone) • Ethcathinone (Ethylpropion) • Ethylamphetamine • Ethylbenzodioxolylbutanamine (EBDB) • Ethylone • Fenethylline • Fenproporex • Flephedrone • Fludorex • Furfenorex • Hordenine • Indanorex • Indanylamphetamine (IAP) • Lophophine (Homomyristicylamine) • Mefenorex • Mephedrone • Methamphetamine (Desoxyephedrine, Methedrine; Dextromethamphetamine, Levomethamphetamine) • Methcathinone (Methylpropion) • Methedrone • Methoxymethylenedioxyamphetamine (MMDA) • Methoxymethylenedioxymethamphetamine (MMDMA) • Methylbenzodioxolylbutanamine (MBDB) • Methylenedioxyamphetamine (MDA; Tenamfetamine) • Methylenedioxyethylamphetamine (MDEA) • Methylenedioxyhydroxyamphetamine (MDOH) • Methylenedioxymethamphetamine (MDMA) • Methylenedioxymethylphenethylamine (MDMPEA; Homarylamine) • Methylenedioxyphenethylamine (MDPEA; Homopiperonylamine) • Methylone • Naphthylamphetamine (NAP) • Ortetamine • Oxaflozane • Parabromoamphetamine (PBA) • Parachloroamphetamine (PCA) • Parafluoroamphetamine (PFA) • Parafluoromethamphetamine (PFMA) • Parahydroxyamphetamine (PHA) • Paraiodoamphetamine (PIA) • Paramethoxyamphetamine (PMA) • Paramethoxyethylamphetamine (PMEA) • Paramethoxymethamphetamine (PMMA) • Paredrine (Norpholedrine, Oxamphetamine) • Phendimetrazine • Phenethylamine (PEA) • Phenmetrazine • Pholedrine • Phenpromethamine • Propylamphetamine • Tiflorex (Flutiorex) • Tyramine (TRA) • Xylopropamine • Zylofuramine; Piperazines: 2,5-Dimethoxy-4-bromobenzylpiperazine (2C-B-BZP) • Benzylpiperazine (BZP) • Methoxyphenylpiperazine (MeOPP; Paraperazine) • Methylbenzylpiperazine (MBZP) • Methylenedioxybenzylpiperazine (MDBZP; Piperonylpiperazine); Others: 2-Aminoindane (2-AI) • 2-Aminotetralin (2-AT) • 4-Benzylpiperidine (4-BP) • Clofenciclan • Cyclopentamine • Cypenamine • Cyprodenate • Feprosidnine • Gilutensin • Heptaminol • Hexacyclonate • Isometheptene • Methylhexanamine • Octodrine • Phthalimidopropiophenone • Propylhexedrine (PHX) • Tuaminoheptane (Tuamine) | | Enzyme
Inhibitors | | | | Others | | | | Serotonergics | | Receptor
Ligands | | | | | | | | | | | | | Agonists: Lysergamides: Dihydroergotamine • Methysergide; Triptans: Almotriptan • Eletriptan • Frovatriptan • Naratriptan • Rizatriptan • Sumatriptan • Zolmitriptan; Tryptamines: 5-CT • 5-MT; Others: CP-135,807 • CP-286,601 • GR-46611 • L-694,247 • L-772,405 • PNU-109,291 • PNU-142,633 Antagonists: Lysergamides: Metergoline • Methiothepin; Tryptamines: Rauwolscine • Yohimbine; Others: BRL-15572 • GR-127,935 • Ketanserin • LY-310,762 • LY-367,642 • LY-456,219 • LY-456,220 • Ritanserin • Ziprasidone | | | | | | | | | | | | | | | | | | | | | | | Agonists: Phenethylamines: 2C-B • 2C-E • 2C-I • 2C-T-2 • 2C-T-7 • 2C-T-21 • DOB • DOC • DOI • DOM • MDA • MDMA • Mescaline • Myristicin; Piperazines: Aripiprazole • mCPP • TFMPP; Tryptamines: 5-CT • 5-MeO-α-ET • 5-MeO-α-MT • 5-MeO-DET • 5-MeO-DiPT • 5-MeO-DMT • 5-MeO-DPT • 5-MT • α-ET • α-Methyl-5-HT • α-MT • Bufotenin • DET • DiPT • DMT • DPT • Psilocin • Psilocybin; Others: A-372,159 • AL-38022A • CP-809,101 • Lorcaserin • MK-212 • PNU-22394 • Ro60-0175 • Vabicaserin • WAY-629 • WAY-161,503 • YM-348 Antagonists: Atypical Antipsychotics: Clozapine • Iloperidone • Melperone • Olanzapine • Paliperidone • Pimozide • Quetiapine • Risperidone • Sertindole • Ziprasidone • Zotepine; Typical Antipsychotics: Chlorpromazine • Loxapine • Pipamperone; Antidepressants: Agomelatine • Amitriptyline • Amoxapine • Etoperidone • Fluoxetine • Mianserin • Mirtazapine • Nefazodone • Nortriptyline • Trazodone; Others: Cinanserin • Cyproheptadine • Deramciclane • Dimebolin • Dotarizine • Eltoprazine • FR-260,010 • Ketanserin • Ketotifen • Methysergide • Pizotifen • Ritanserin • RS-102,221 • SB-200,646 • SB-206,553 • SB-221,284 • SB-228,357 • SB-242,084 • SB-243,213 • SDZ SER-082 • Xylamidine | | | | | | | | | | | | | | | | | | | Agonists: Lysergamides: Ergotamine • LSD Antagonists: Methiothepin * Note that the 5-HT5B receptor is not functional in humans. | | | | | | | | | | | | Reuptake
Inhibitors | | | Releasing
Agents | | | Enzyme
Inhibitors | | | | Others | | | |
