Monoamine oxidase type B inhibitors

Monoamine oxidase type B inhibitors (rasagiline, selegiline) reduce the metabolism of dopamine by MAO-B. They are useful to delay disease progression in the early stages of the disease and as an adjunct to levodopa. 

Other substances that are being evaluated in Alzheimer s disease include the antioxidant vitamin E, the monoamine oxidase type B inhibitor, selegeline (see p. 425) and the plant extract gingko biloba, which is though to have antioxidant and cholinergic activity. Oestrogens and nonsteroidal anti-inflammatory agents may also have protective effects. 

Mendlewicz J, Youdim MB (1983) L-Deprenil, a selective monoamine oxidase type B inhibitor, in the treatment of depression a double blind evaluation. Br J Psychiatry 142 508-511... 

Lohle, M. and Storch, A. 2012. Effects of monoamine oxidase Type B inhibitors on motor... 

MAOI non-selective monoamine oxidase (A/B) inhibitors RIMA reversible inhibitor of monamine oxidase type A SSRI selective serotonin (5-HT) reuptake inhibitors SNRI serotonin/noradrenaline reuptake inhibitor SNARI selective noradrenaline (NA) reuptake inhibitor NA = 5-HT — DA potency of the drug is very similar in raising the level of both (or all three) monamines NA > 5-HT more selective for NA 5-HT>NA more selective for 5-HT NA increases the release of NA. 

Which of the following is a selective inhibitor of monoamine oxidase type B (MAO-B) and, therefore, useful in treating parkinsonism ... 

Monoamine oxidase (MAO) inhibitors block the oxidative deamination of monoamines, i.e. norepinephrine and serotonin by inhibiting monoamine oxidase type A (MAO-A) and dopamine also by monoamine oxidase type B (MAO-B) inhibition, thereby increasing these neurotransmittors at their receptors in the brain and in the periphery. MAO-A... 

The authors proposed that selegiline may have caused this effect by inhibiting dopamine metabolism, and that selegiline may not be as specific an inhibitor of monoamine oxidase type B as previously thought. 

Selegiline is a relatively selective and irreversible inhibitor of monoamine oxidase type B, which has been used in the treatment of Parkinson s disease. It was originally suggested that selegiline may be neuroprotective. However, in a prospective double-blind study no such action was seen (1). On the other hand, selegiline does delay the start of disability, determined by the need for levodopa and progression of parkinsonian signs and symptoms (2). 

MPTP causes parkinson-like extrapjramidal dysfunction by destroying dopaminergic neurons in the nigrostriatal tract. This neurotoxic action requires the formation of toxic metabolites from the metabolism of MPTP by monoamine oxidase type B. Toxicity is prevented by selegiline, a selective inhibitor of MAO type B. MPTP is used as an experimental tool in animal models of parkinsonism. The answer is (E). 

MAO inhibitors Drugs that inhibit monoamine oxidase type A which metabolizes norepinephrine and serotonin, or monoamine oxidase type B, which metabolizes dopamine... 

Fowler CJ, Mantle TJ, Tipton KF. The nature of the inhibition of rat liver monoamine oxidase types A and B by the acetylenic inhibitors clorgyline, 1-deprenyl and pargyline. Biochem Pharmacol 1982 31(22) 3555-3561. 

The drugs that can cause a serotonin syndrome when they are combined with SSRIs include monoamine oxidase inhibitors (including reversible inhibitors of monoamine oxidase types A and B), dextromethorphan,... 

It is found to be an irreversible inhibitor of both monoamine oxidase types A and B. 

Selegiline [(/ )(-)-W,a-dimethyl-W-(2-propynyl)benzeneethanamine, Elde-pryl. Deprenyl, 1] is a phenethylamine derivative which is pharmacologically active in the levo form. It is indicated as adjuvant treatment with levo-dopa in Parkinson s disease, and is supplied as a 5 mg tablet of selegiline hydrochloride. It belongs to the class of type B inhibitors of monoamine oxidase (MAOI-B). At high doses (>40 mg/day in man), selegiline loses its MAOI-B specificity and also inhibits MAO-A. 

Ubiquitous mitochondrial monoamine oxidase [monoamine oxygen oxidoreductase (deaminating) (flavin-containing) EC 1.4.3.4 MAO] exists in two forms, namely type A and type B [ monoamine oxidase (MAO) A and B]. They are responsible for oxidative deamination of primary, secondary, and tertiary amines, including neurotransmitters, adrenaline, noradrenaline, dopamine (DA), and serotonin and vasoactive amines, such as tyramine and phenylethylamine. Their nonselec-tive and selective inhibitors ( selective MAO-A and -B inhibitors) are employed for the treatment of depressive illness and Parkinson s disease (PD). 

Monoamine oxidase exists in the human body in two molecular forms, known as type A and type B. Each of these isozymes has selective substrate and inhibitor characteristics. Neurotransmitter amines, such as norepinephrine and serotonin, are preferentially metabolized by MAO-A in the brain. MAO-B is more likely to be involved in the catabolism of human brain dopamine, although dopamine is also a substrate for MAO-A. 

R.W. Fuller, S.K. Hemrick-Luecke, B.B. Molloy, A/-[(2-o-lndophenoxy)ethyl]cyclopro-pylamine hydrochloride (LY121768), a potent and selective irreversible inhibitor of type A monoamine oxidase, Biochem. Pharmacol. 32 (1983) 1243-1249. 

Monoamine oxidase inhibitors. The monoamine oxidase inhibitors (MAOIs) inhibit the intracellular catabolic enzyme monoamine oxidase. There are two types of monoamine oxidase MAO-A and MAO-B, both of which metabolize tyramine and dopamine. In addition, MAO-A preferentially metabolizes norepinephrine, epinephrine, and serotonin, and MAO-B preferentially metabolizes phenylethylamine (an endogenous amphetamine-like substance) and N-methylhistamine (Ernst, 1996). Some MAOIs are selective for A or B and some are nonselective (mixed). In addition, irreversible MAOIs (e.g., phenelzine, tranylcypromine) are more susceptible to the cheese effect than are the reversible agents (e.g., moclobemide). 

Monoamine oxidase (MAO) inhibitors, nonselective (Types A,B) phenelzine sulfate tranylcypromine sulfate... 

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