5-Hydroxytryptamine-thyrotropin releasing hormone interactions in the spinal cord: effects on parameters of sexual behaviour in the male rat.

In the studies of sexual behaviour in male rats reported here, intrathecal administration of 5-hydroxytryptamine (5-HT) together with thyrotropin releasing hormone (TRH) caused a marked and specific increase in mount and intromission latencies. In contrast, injection of either of the two compounds alone elicited only minor effects. These findings are discussed in relation to the co-existence of 5-HT and TRH in nerve endings in the ventral horn of the spinal cord originating in supraspinal, medullary nuclei.