Monoamine Oxidases A and

Dopamine. Dopamine (DA) (2) is an intermediate in the synthesis of NE and Epi from tyrosine. DA is localized to the basal ganglia of the brain and is involved in the regulation of motor activity and pituitary hormone release. The actions of DA are terminated by conversion to dihydroxyphenylacetic acid (DOPAC) by monoamine oxidase-A and -B (MAO-A and -B) in the neuron following reuptake, or conversion to homovanillic acid (HVA) through the sequential actions of catechol-0-methyl transferase (COMT) and MAO-A and -B in the synaptic cleft. 

Saura, J, Bleuel, Z, Ulrich, J, Mendelowitsch, A, Chen, K, Shih, JC, Malherbe, P, Da Prada, M and Richards, JG (1996) Molecular neuroanatomy of human monoamine oxidases A and B revealed by quantitative enz5mie radioautoradiography and in situ hybridization histochemistry. Neurosci. 70 755-774. 

Cusin, C., Serretti, A., Zanardi, R. etal. (2002). Influence of monoamine oxidase A and serotonin receptor 2A polymorphisms in SSRI antidepressant activity. Int.. Neuropsychopharmacol, 5, 27-35. 

Berlin, I., Spreux-Varoquaux, O., Said, S., Launay, 1. Effects of past history of major depression on smoking characteristics, monoamine oxidase-A and -B activities and withdrawal symptoms in dependent smokers. Drug Alcohol Depend. 45 31, 1997. 

Isoenzymes Structurally related enzyme proteins that catalyse very similar or identical reactions (e.g., monoamine oxidase A and B, cytochrome P-450). 

Bach AW, Lan NC, Johnson DL, et al. cDNA cloning of human liver monoamine oxidase A and B molecular basis of differences in enzymatic properties. Proc Natl Acad Sci USA 1988 85(13) 4934—4938. 

Salach JI, Singer TP, Castagnoli N, Jr, et al. Oxidation of the neurotoxic amine l-methyl-4-phenyl-l,2,3,6-tetrahydropyridine (MPTP) by monoamine oxidases A and B and suicide inactivation of the enzymes by MPTP. Biochem Biophys Res Commun 1984 125(2) 831-835. 

Two enzymes are concerned in the metabolism of catecholamines, namely monoamine oxidase, which occurs mainly intraneuronally, and catechol-O-methyltransferase, which is restricted to the synaptic cleft. The importance of the two major forms of monoamine oxidase, A and B, will be considered elsewhere. 

Salichon N, Gaspar P, Upton AL, Picaud S, Hanoun N, Hamon M, De Maeyer EE, Mnrphy DL, Mossner R, Lesch KP, Hen R, Seif I (2001) Excessive activation of serotonin (5-HT) IB receptors disrupts the formation of sensory maps in monoamine oxidase A and 5-HT transporter knock-out mice. J Neurosci 21 884-896... 

NT038 Hauptmann, N., and J. C. Shih. 2-Naphthylamine, a compound found in cigarette smoke, decreases both monoamine oxidase A and B catalytic activity. Life Sci 2001 68(11) 1231-1241. 

Nonselective and Irreversible Inhibitors of Monoamine Oxidase A and Monoamine Oxidase B... 

Vanyuko r, Michael M., Howard B. Moss, Ling M. Yu, and Ranjan Deka. 1995b. "A Dinucleotide Repeat Polymorphism at the Gene for Monoamine Oxidase A and Measures of Aggressiveness." Psychiatry Research 59 35-41. 

Youdim MB, WeinstockM. Therapeutic applications of selective and non selective inhibitors of monoamine oxidase A and B that do not cause significant tyramine potentiation. Neurotoxicology. 2004 25 243-250. 

DISTRIBUTION OF MONOAMINE OXIDASES A AND B mRNAs IN THE RAT BRAIN BY IN SITU HYBRIDIZATION... 

Flavones, coumarins (neoflavonoids), and other oxygen-containing compounds were found to inhibit monoamine oxidases A and B in a reversible and time-independent manner. 

GINKGO BILOBA EXTRACT AND INHIBITION OF MONOAMINE OXIDASE A AND B IN LIVING HUMAN BRAIN... 

Desautels A, Turecki G, Montplaisir J, Brisebois K, Sequeira A, Adam B, Rouleau GA. Evidence for a genetic association between monoamine oxidase A and restless legs syndrome. Neurology 2002 59 215-219. 

An alternative therapeutic strategy has focused on improving cognitive features of HD, and the effect of this treatment on gene expression has been studied [76], R6/2 mice were treated from 5 weeks old, when they exhibit spatial learning difficulties, with a cocktail of tacrine (an acetylcholine esterase inhibitor, which results in a global increase of brain acetylcholine levels), moclobemide (an antidepressant that inhibits monoamine oxidase A and... 

Above recommended doses, irreversibiy biocks both monoamine oxidase A and monoamine oxidase B from breaking down norepinephrine, serotonin, and tyramine as weii as dopamine and phenethyiamine... 

Edmondson DE, Binda C, Mattevi A. Structural insights into the mechanism of amine oxidation by monoamine oxidases A and B. Arch. Biochem. Biophys. 2007 464 269-276. 

Monoamine oxidases are flavoproteins that contain one molecule of FAD per molecule. There are two major types of monoamine oxidase (A and B), whose relative concentration varies in tissues of the same species. In general, the A form of the enzyme is more active with endogenous neurotransmitter amines (serotonin, norepinephrine, and epinephrine), whereas the B form is more active toward xenobiotic amines such as 2-phenethylamine. 

Strolin Benedetti M, Keane PE (1980) Differential changes in monoamine oxidase A and B activity in the aging brain. J Neurochem 35 1026-1032 Student AK, Edwards DJ (1977) Subcellular localization of types A and B monoamine oxidase in rat brain. Biochem Pharm 26 2337-2342 Tanner CM, Goldmann SM (1996) Epidemiology of Parkinson s disease. Neurol Clin 14 317-335... 

The answer is c. (Murray, pp 347-358. Scriver, pp 3-45. Sack, pp 97-158. Wilson, pp 361-391.) Dopamine is produced from L-dopa, which in turn is made from tyrosine. Therapy with the L-dopa precursor increases dopamine concentrations and improves the rigidity and immobility that occur in Parkinson s disease. Dopamine is degraded in the synaptic cleft by monoamine oxidases A and B (MAO-A and MAO-B), producing 3,4-dihydroxyphenylacetaldehyde (DOPAC). DOPAC is in turn broken down to homovanillic acid, which can be measured in spinal fluid to assess dopamine metabolism. Inhibitors of MAO-A and MAO-B have some use in treating Parkinson s disease. The metabolism of histidine or alanine is not related to that of dopamine, but phenylalanine is a precursor of tyrosine and L-dopa. 

The flavoenzymes monoamine oxidase A and B (MAO-A, MAO-B)1271 catalyze the oxidative deamination of various primary and secondary amines and the oxidation of tertiary amines. Their physiological role, as the various synonyms such as epineph-... 

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