Role of some types of serotonin receptors in murine hypophyseal-testicular complex activation induced by the presence of a female

Abstract

Placement of a sexually receptive female mouse behind a partition that prevents physical contacts, but permits it to see and smell caused an increase in the blood levels of testosterone in male mice. The selective 5-HTIA-serotonin receptor agonist 08-OH- DPAT (0.1 mg/kg) and the mixed 5-HTIA/IB agonist eltoprazine, 3.0 and 10.0 mg/kg, blocked the activating effect of female exposure on the male pituitary-testicular system. The 5-HT/-receptor agonist p-MPPI (0.2 mg/kg) prevented the inhibitory effects of 8-OH-DPATand eltoprazine. The 5-HT/B-receptor agonist CGS- 12066A (1.0 and 2.0 mg/kg) exerted no effect while the mixed 5-HTIB/2C-receptor agonist TFMPP (5.2 mg/kg) inhibited a female-induced increase in the levels of male blood testosterone. The 5-HT/-receptor agonist keranserin (1.0 and 2.0 mg/kg) prevented a female-induced increase in the levels of testosterone. The 5-HT3-receptor agonist ondansetron (0.05 and 0.1 mg/kg) elevated the baseline level of plasma testosterone, but blocked receptive female-induced activation of the male hypothalamic-pituitary-testicular system (HPTS). It is concluded that 5-HTIA-receptors are involved in the control of male sexual activation. At the same time different types and even subtypes of the same type of 5-HT-receptors produce varying inhibitory and activating effects on the receptive female-induced activation of HPTS. Blocking of the female-induced activation of HPTS seems to be realized by involving 5-HTu- and 5-HT2C-receptors and its activation occurs with the participation of 5-HT^- and 5- HT3-receptors.