5-HT1A receptors: differential involvement in female and male sexual behavior in the rat.

The peripheral administration of the serotonin type 1A (5-HT1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH DPAT) inhibited lordosis behavior in ovariectomized rats primed with estradiol benzoate. 8-OH DPAT was ineffective at 0.01 mg/kg, whereas inhibition occurred at the 0.03, 0.1, 0.3, 1, and 3 mg/kg doses. On the other hand, 8-OH DPAT enhanced various measures of male sexual behavior both in males and in females treated chronically with testosterone propionate. In males, 1 mg/kg 8-OH DPAT reduced ejaculation latencies and the number of intromissions prior to ejaculation. In females, 0.1 and 1 mg/kg 8-OH DPAT increased mount frequencies. These data indicate differential involvement of 5-HT1A receptors in male and female sexual behavior. In view of these and other recent data the authors conclude that activity at 5-HT2 receptors facilitates, whereas activity at 5-HT1 receptors may either facilitate or inhibit lordosis behavior. Furthermore, it is proposed that 5-HT1A receptors mediate inhibitory effects, whereas 5-HT1B receptors mediate presynaptic, facilitatory effects of serotonin.