MAO monoamine

MAO (monoamine oxidase) inhibitor. An agent that blocks one of the enzymes that deaminates amines. 

The deamination of DA to DOPAC can be prevented by MAOb inhibitors such as selegiline while COMT inhibitors stop its further o-methylation to HVA and the conversion of dopa to OMD. COMT inhibitors can act just peripherally (entacapone) or in the CNS as well (tolcapone). DD — dopa decarboxylase MAO—monoamine oxidase COMT—catechol-o-methyl transferase... 

MAP Macrophage-activating 6ctor MAO Monoamine oxidase MAP Monophasic action potential... 

Ach, acetylcholine CNS, central nervous system CD, carbidopa COMT, catechol-O-methyltransferase D1, a class of dopamine receptors which includes D, and D5 subtypes D2, a class of dopamine receptors which includes D2, D3, and D4 subtypes DA, dopamine LD, levodopa MAO, monoamine oxidase MD, maintenance dose NMDA, N-methyl-D-aspartate. 

CYP, cytochrome P-450 isoenzyme MAO, monoamine oxidase. Data from references 59-65. 

BUN, blood urea nitrogen CBC, complete blood cell count CNS, central nervous system CYP, cytochrome P-450 isoenzyme LFT, liver function test MAO, monoamine oxidase QTc, Q-T interval corrected for heart rate SCr, serum creatinine TMP-SMX, trimethoprim-sulfamethoxazole. 

The first two antidepressants, iproniazid and imipramine, were developed in the same decade. They were shown to reverse the behavioural and neurochemical effects of reserpine in laboratory rodents, by inhibiting the inactivation of these monoamine transmitters (Leonard, 1985). Iproniazid inhibits MAO (monoamine oxidase), an enzyme located in the presynaptic neuronal terminal which breaks down NA, 5-HT and dopamine into physiologically inactive metabolites. Imipramine inhibits the reuptake of NA and 5-HT from the synaptic cleft by their transporters. Therefore, both of these drugs increase the availability of NA and 5-HT for binding to postsynaptic receptors and, therefore, result in enhanced synaptic transmission. Conversely, lithium, the oldest but still most frequently used mood stabiliser (see below), decreases synaptic NA (and possibly 5-HT) activity, by stimulating their reuptake and reducing the availability of precursor chemicals required in the biosynthesis of second messengers. 

MAO (monoamine oxidase) inhibitor Non-selective inhibitors of the enzyme monoamine oxidase. An example is iproniazid, one of the first-generation anti-... 

FIGURE 14-3 Synthesis and metabolism of histamine. Solid lines indicate the pathways for histamine formation and catabolism in brain. Dashed lines show additional pathways that can occur outside the nervous system. HDC, histidine decarboxylase HMT, histamine methyltransferase DAO, diamine oxidase MAO, monoamine oxidase. Aldehyde intermediates, shown in brackets, have been hypothesized but not isolated. 

FIGURE 46-3 Synthesis and metabolism of dopamine. MAO, monoamine oxidase COMT, catechol-O-methyltransferase HVA, homovanillic acid DOPAC, 3,4-dihydroxyphenylacetic acid. 

COMT, catechol-O-methyttransferase CR, controlled release MAO, monoamine oxidase ODT, orally disintegrating tablet. °Dosages may vary beyond stated range. 

COMT = Catechol-O-Methyl transferase MAO = Monoamine Oxidase HMMA = Hydroxy Methoxy Mandelic Acid... 

MAO (monoamine oxidase) two related enzymes that inactivate neurotransmitters such as serotonin, dopamine, and norepinephrine. 

Varicosity of a noradrenergic neuron showing synthesis and storage of norepinephrine. Also shown Is the release of norepinephrine (NE) and multiple routes for degradation. COMT, catechol-O-methyltransferase MAO, monoamine oxidase. 

Primary route of metabolism of norepinephrine and epinephrine. COMT, catechol-0-methyltransferase MAO, monoamine oxidase. 

AADC Amino acid decarboxyiase MAO Monoamine oxidase... 

The figure below illustrates proposed sites of action of drugs. For each drug listed, select the site of action that the drug is most likely to inhibit (a, a receptor p, p receptor COMT, catechol-O-methyltransferase MAO, monoamine oxidase NE, norepinephrine NMN, normetanephrine). 

Note. MAOI=monoamine oxidase inhibitor MAO=monoamine oxidase. Selective at lower doses, nonselective at higher doses. 

The first generation of antidepressants, MAO (monoamine oxidase) inhibitors, inhibited neurotransmitter degradation by inhibiting monoamine deoxidase, a flavin containing enzyme, found in the mitochondria of neurons and other cell types, that oxidatively deaminates naturally occurring sympathomimetic monoamines, such as norepinephrine, dopamine, and serotonin within the presynapse. In 1952, isoniazid and its isopropyl derivative, iproniazid (1), were developed for the treatment of tuberculosis, where it was subsequently found that these agents had a mood enhancing effect on... 

Meperidine Demerol 50-100 mg every 3 hours An effective pain reliever but potentially fatal if given in combination with antidepressants known as MAO (monoamine oxidase) inhibitors can also cause seizures... 

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