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 noradrenergic system on the pharmacological reversal of the sexual inhibition 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/kg), and naloxone (3 mg/kg). All drugs, at the doses tested, were able to increase the percentage of sexually exhausted intact rats showing copulatory behavior 24 h after a sexual satiation session. In N-(2-chloroethyl)-N-ethyl-2-2-bromobenzylamine (DSP4)-lesioned, sexually exhausted animals, naloxone and 8-OH-DPAT lost their stimulatory effect on sexual behavior; yohimbine treatment was still able to markedly increase the percentage of satiated rats mounting, intromitting, and exhibiting 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 copulatory behavior in sexually exhausted rats. Results are in line with previous data showing that the sexual behavioral variables more directly addressing motivational components are severely affected by sexual satiation.