Flesinoxan: a prosexual drug for male rats.

Two tests were carried out to compare the stimulatory (i.e., prosexual) effects of the 5-HT1A receptor agonists flesinoxan and 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) on sexual behavior in male Wistar rats. Two groups of rats were used: normal males and males with impaired masculine sexual behavior due to neonatal treatment with the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD). In Experiment 1, flesinoxan (0.3 and 1.0 mg/kg) stimulated ejaculation frequency and number of animals displaying this behavior, both in controls and ATD males. With 0.3 mg/kg flesinoxan ATD males did not differ from controls in ejaculation frequencies. There was a concomitant decrease in latency to first ejaculation. No 'premature' ejaculations (i.e., at first or second intromission) were observed. In Experiment 2, the effects of 0.4 mg/kg 8-OH-DPAT, 0.3, 1.0 and 3.0 mg/kg flesinoxan and saline were tested in two ejaculation series. 'Premature' ejaculations only occurred during first ejaculation series with 8-OH-DPAT in 8 of 10 controls and in 6 of 9 ATD males; it did not occur during flesinoxan treatment nor in the second ejaculation series with 8-OH-DPAT treatment. Thus, flesinoxan stimulates sexual behavior in control rats and in rats with impaired sexual behavior. Unlike 8-OH-DPAT flesinoxan does not render them into 'premature' ejaculators. Therefore, flesinoxan could be considered a prosexual drug for male rats.