5-HT(2A) and 5-HT(2C) Serotonin Receptors Differentially Modulate Mouse Sexual Arousal and the Hypothalamo-Pituitary-Testicular Response to the Presence of a Female.

摘要

The role of 5-HT(2A) and 5-HT(2C) subtypes of serotonergic receptors in the control of sexual behavior and plasma testosterone regulation was studied in male CBA mice exposed to a sexually receptive female separated by a transparent partition. Introduction of the receptive female induced sexual motivation and arousal in males, as evidenced by a prolonged time spent at the partition, unsuccessful attempts to step across it and a significant increase in plasma testosterone levels. Administration of 5-HT(2A) receptor antagonists ketanserin (1.0 and 2.0 mg/kg i.p.) or cyproheptadine (1.0 and 2.0 mg/kg i.p.) diminished the behavioral components and prevented the hormonal components of male sexual arousal. Administration of the selective 5-HT(2C) antagonist RS 102221 (1.0 and 2.0 mg/kg) considerably increased the time spent by males at the partition (p < 0.001) and, at the dose of 2.0 mg/kg, increased plasma testosterone levels (p < 0.01). Administration of ritanserin - a nonselective 5-HT(2A/2C) antagonist and, to a smaller degree, 5-HT(2B) antagonist - at doses of 0.1 and 0.5 mg/kg did not significantly influence male behavior and the activating effect of the presence of a female on the hypothalamo-pituitary-testicular system, although it increased resting testosterone levels (p < 0.05). The present findings suggest that 5-HT(2A)/5-HT(2C) receptors may be involved in the neural control of male sexual motivation and arousal, presumably by exerting reciprocal facilitative (5-HT(2A)) or suppressive (5-HT(2C)) influences.