Stimulatory effects of the noradrenergic neurotoxin DSP4 on sexual behavior in male quail

Four separate experiments were carried out to test in castrated male Japanese quail the effects on testosterone-induced sexual behavior of the neurotoxic drug N-(2-chlorethyl)-N-ethyl-2- bromobenzylamine hydrochloride (DSP4). In each experiment, DSP4 enhanced some aspects of the testosterone-induced sexual behavior. The latency between the start of testosterone treatment and the first occurence of copulatory behavior was decreased, the behavior frequency and duration were increased, and the latency between the introduction of a stimulus female and the first sexual behavior was decreased. The effects could be reversed by concurrent treatment with the alpha-adrenergic agonist, phenylephrine. The stimulatory effects of DSP4 on behavior were not seen in castrated birds which did not receive a concurrent treatment with testosterone and they were associated with a significant decrease of the norepinephrine concentration in the hypothalamus. These results suggest that the noradrenergic system plays an inhibitory role in the control of copulatory behavior of quail similar to what has been described in the ring dove.