Harmine, a hallucinogen with potent monoamine oxidase inhibitory properties, induced abnormal behavior, including tremor, scratching, head twitch and cage biting, in the mouse. A dose-dependent tremor was produced by all routes of administration of harmine. Although oxotremorine tremor was markedly suppressed by atropine, harmine tremor was unaffected by cholinergic drugs, remarkably inhibited...