PARTICIPATION OF THE CENTRAL NORADRENERGIC SYSTEM IN THE REESTABLISHMENT OF COPULATORY-BEHAVIOR OF SEXUALLY EXHAUSTED RATS BY YOHIMBINE, NALOXONE, AND 8-OH-DPAT

This study analyzes the impact of a neurotoxic lesion of the central n oradrenergic system on the pharmacological reversal of the sexual inhi bition present at sexual exhaustion, by IP treatment with yohimbine (2 mg/kg), 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (0.25 mg/k g), and naloxone (3 mg/kg), All drugs, at the doses tested, were able to increase the percentage of sexually exhausted intact rats showing c opulatory behavior 24 h after a sexual satiation session. In N-(a-chlo roethyl)-N-ethyl-2-2-bromobenzylamine (DSP4)-lesioned, sexually exhaus ted animals, naloxone and 8-OH-DPAT lost their stimulatory effect on s exual behavior; yohimbine treatment was still able to markedly increas e the percentage of satiated rats mounting, intromitting, and exhibiti ng the ejaculatory motor pattern, but inhibited seminal emission, The data strongly suggest that the integrity of the central noradrenergic system is essential for the pharmacological reestablishment of copulat ory behavior in sexually exhausted rats, Results are in line with prev ious data showing that the sexual behavioral variables more directly a ddressing motivational components are severly affected by sexual satia tion.