Multiple ejaculations and chronic fluoxetine: Effects on male rat copulatory behavior

Male rats were treated with fluoxetine (FLX) or vehicle daily for 14 days a nd copulatory behavior tested on day 15. Rats were either mated to three ej aculations or to sexual exhaustion. Both standard measures and the mount bo ut analysis were used to evaluate the effects of the chronic FLX on male ra t copulatory behavior. Only 56.25% of the animals treated with FLX achieved three ejaculations. FLX inhibited the consumatory aspect of male sexual be havior, especially the ability to achieve three ejaculations, but there was no effect on the propensity of the male to pursue the female. These differ ences were observed for the first three ejaculations. Analysis of the last three ejaculations in those animals that mated to exhaustion did not reveal an effect of FLX. The behavioral pattern of FLX-treated animals during the first three ejaculations resembled that observed during the last three eja culatory series in the vehicle-treated animals that mated to exhaustion. Th e results are discussed in terms of the serotonergic effects on male rat se xual behavior. (C) 2000 Elsevier Science Inc.