PROLONGATION OF THE EJACULATION LATENCY IN THE MALE-RAT BY THIORIDAZINE AND CHLORIMIPRAMINE

Thioridazine (3 mg/kg) and chlorimipramine (1.5-6.0 mg/kg) prolonged the ejaculation latency and increased the number of mounts but did not change the number of intromissions preceding ejaculation. Blockade of peripheral and central noradrenaline receptors by phentolamine and phenoxybenzamine respectively resulted in a suppression of all aspects of the sexual behavior with increasing doses. dl-5-HTP (25-100 mg/kg) in combination with an inhibitor of peripheral 5-HTP decarboxylase (benserazide, 25 mg/kg) produced, like chlorimipramine and thioridazine, a prolongation of ejaculation latency and an increase in the number of mounts preceding ejaculation. Selective inhibition of 5-HT reuptake however, by zimelidine (0-20 mg/kg) or alaproclate (0-20 mg/kg) did not affect the mating behavior. At higher doses of these drugs some animals failed to initiate sexual activities. There was an increase in the postejaculatory interval but no change in the ejaculatory latency. It is concluded that the prolonged ejaculation latencies observed following treatment with thioridazine or chlorimipramine is not due to a blockade of central or peripheral adrenergic α-receptors. © 1979 Springer-Verlag.