THE SELECTIVE SEROTONIN REUPTAKE INHIBITOR FLUOXETINE REDUCES SEXUAL MOTIVATION IN MALE RATS

A male rat put in an open-field arena in which it is free to spend tim e in the vicinity of-but not in contact with-an estrous female, or in the vicinity of a male, usually spends more time with the female than with the male or elsewhere. Tentatively, the percentage of time spent in the vicinity of the female in this paradigm may be regarded as a me asure of sexual motivation. In humans, treatment with selective seroto nin reuptake inhibitors (SSRIs) may cause reduced libido. To investiga te to what extent serotonin reuptake inhibition influences sexual moti vation also in rats, we have tested the effect of subchronic treatment with fluoxetine on the behavior in the sexual motivation test describ ed above; in addition, the effect of fluoxetine on male copulatory beh avior was studied. Fluoxetine significantly reduced sexual motivation at subchronic but not at acute administration; moreover, fluoxetine-tr eated rats displayed an increased ejaculation latency. It is concluded that humans and rats respond similarly to the SSRI fluoxetine with re spect to various aspects of sexual behavior. (C) 1998 Elsevier Science Inc.