The comparative influence of pyrazidol, inkazan and other antidepressant monoamine oxidase inhibitors on the pressor effect of tyramine

In experiments on conscious normotensive male Wistar rats the new antidepressants, reversible MAO-A inhibitors, pyrazidole and incazane, as well as moclobemid increased the pressor effect of orally administered tyramine. The drugs potentiated also the pressor effect of intravenous tyramine. More prolonged potentiation of tyramine action was produced by moclobemid, less prolonged by incazane. The potentiation by the studied MAO-A inhibitors of the pressor effect of tyramine reflects the inhibition of the activity of MAO-A and the first-pass metabolism of tyramine in the gut and liver, as well as the inhibition of intraneuronal MAO activity in noradrenergic nerve endings and the potentiation of sympathetic activity.