Studies on hyperactivity in rats given tranylcypromine stereoisomers and reserpine

Hyperactivity, salivation, piloerection, exophthalmia and ejaculation occurred in rats given reserpine (5 mg/kg i.p.) 2 hr after an oral dose (5 mg/kg) of trans-dl-2-phenylcyclopropylamine (tranylcypromine, dl-Tcp). The same syndrome occurred in rats given the d-isomer (d-Tcp) plus reserpine but not in rats given the l-isomer (l-Tcp) lus reserpine. Neither alpha methyl-p-tyrosine (2 X 150 mg/kg s.c.) nor parachlorophenylalanine (200 mg/kg s.c.) pretreatment prevented the hyperactivity syndrome. The results suggest that mainly MAO inhibition and release of monoamines are involved in the hyperactivity syndrome produced by dl-Tcp plus reserpine.