Role of descending monoaminergic neurons in the control of sexual behavior: effects of intrathecal infusions of 6-hydroxydopamine and 5,7-dihydroxytryptamine.

The present study concerns the possible participation of descending monoamine pathways in the control of sexual behavior. Male and female rats received micro-injections of the neurotoxins, 6-hydroxydopamine (6-OHDA) or 5,7-dihydroxytryptamine (5,7-DHT), in the spinal subarachnoid space, which were found to deplete spinal synaptosomal uptake of radiolabeled noradrenaline and serotonin to 46.7% and 34.5%, respectively. Whereas intrathecal 5,7-DHT did not affect sexual behavior appreciably, female 6-OHDA-treated rats showed less sexual receptivity and proceptivity when exposed to constant estradiol; similarly treated males had prolonged post-ejaculatory refractory periods and were more sensitive than controls to androgen deprivation.