Sexual experience did not affect the long-term sexual behavior inhibition of male rats treated with fluoxetine

Antidepressants, including tricyclics, monoamine oxidase inhibitors and selective serotonin reuptake inhibitors cause sexual dysfunctions such as decreased sexual desire, erectile difficulties, and delayed ejaculation. Studies have shown that treatment with fluoxetine inhibits several components of sexual behavior in male rats. It is known that sexual experience improves the sexual behavior of male rats. Thus, the effects of sexual experience were examined in male rats during long-term treatment with fluoxetine or vehicle. Rats treated with 10mg/kg fluoxetine or vehicle daily (28 days) were observed for sexual behavior at the 14th, 21st, and 28th day of treatment. Long-term administration of fluoxetine increased the mount latency in control rats in the first session; no differences were observed in other parameters on the same day. Still in the control group, the mount and intromission latencies gradually decreased, whereas the number of intromissions and ejaculations increased over the sessions. The group in long-term treatment with fluoxetine also showed reduced mount and intromission latencies, although latencies remained significantly higher as compared to the control group. Fluoxetine-treated rats showed increased mount and intromission rates on the 28th day of treatment in relation to the first day. These data suggest that the impairment caused by long-term treatment with fluoxetine persists throughout the sessions despite the rats’ sexual experience.