In vivo Monoamine Oxidase Inhibition Measured by Potentiation of Tryptamine Convulsions in Rats

Abstract

The in vivo monoamine oxidase (MAO) inhibitory potency of a number of drugs was tested by measuring their activity as potentiators of the convulsant effects of tryptamine. Effective MAO inhibitors. arranged in descending order of potency, included harmine (s.c.) tranylcypromine. SKF cis 385, d-PIH, dl-PIH, harmine (oral). RO-4-1018, nialamide, phenelzine, iproniazid, and isonicotinyl-PIH. Compounds ineffective as MAO inhibitors included diphenhydramine, tripelennamine, isoniazid, dihydroergotamine, mescaline, SKF 525-A, SKF 5-A, procaine, and procaine amide.