Role of Lower Brain Stem in Regulating Sexual Behaviors in Male and Female Rats.

用射频毁损器损毁去卵巢大鼠的中缝隐核(ROBN)或中缝大核(RMGN)，观察中缝延髓核团对雌雄行为的调节作用。术后4~5周，所有女性均植入含雌二醇(E_2)的硅胶管。植入后2天开始性行为测试，连续5天每天进行。ROBN损伤-女性在第一次测试中显示出高水平的前凸商(LQ)，与非脑外科手术和假手术女性相比。RMGN损伤组的平均LQ与对照组相当。此外，ROBN损伤组甩耳的发生率高于其他组。这些结果表明，中缝隐核对雌性大鼠性行为的调节具有抑制作用。在去势雄性大鼠，ROBN或RMGN被破坏。术后4~5周，所有男性均植入含睾酮的硅胶管。给药后1周开始性行为测试，每隔1周进行3次性行为测试。ROBN损伤组的坐位、插入和射精频率均低于RMBN损伤组、非颅脑手术组和假手术组。这些结果表明，与雌性大鼠相比，中缝隐核在调节雄性大鼠性行为方面起着易化作用。此外，经5-羟色胺合成抑制剂对氯苯丙氨酸(PCPA)治疗后，ROBN病变男性的性行为频率高于非PCPA治疗的ROBN病变男性，但低于PCPA治疗的非颅脑手术对照组男性。因此，PCPA可能作用于ROBN以外的5-羟色胺能神经元，促进雄性大鼠性行为。

Roles of the medullary raphe nuclei in regulating female and male sexual behaviors were investigated in rats.In ovariectomized rats, the raphe obscurus nucleus (ROBN) or the raphe magnus nucleus (RMGN) was destroyed by radio frequency lesion generator. Four-5 weeks after operations, all females were implanted with a Silastic tubing containing estradiol (E_2). Sexual behavioral tests were started 2 days after E_<> implantations and carried out daily for 5 days. ROBN lesion-females showed high levels of lordosis quotient (LQ) in the first test, when compared with those of non-brain surgery and sham operated females. The mean LQ of RMGN lesion group was comparable to those of control groups. In addition, incidence of ear-wiggling in ROBN lesion group was higher than those in other groups. These results suggest that the raphe obscurus nucleus play an inhibitory role in regulating female rat sexual behaviors.In castrated male rats, ROBN or RMGN was destroyed. Four-5 weeks after operation, all males were implanted Silastic tubings containing testosterone. Sexual behavior tests were started 1 week after testosterone administration and 3 tests were carried out 1 week intervals. In ROBN lesion group, frequencies of mounting, intromission and ejaculation were lower than those in RMBN lesion, non-brain surgery and sham operated groups. These results suggest that in contrast to the female case, the raphe obscurus nucleus play a facilitatory role in regulating male rat sexual behaviors. Furthermore, after treatment with p-chlorophenylalanine (PCPA, an inhibitor for serotonin synthesis), ROBN lesion-males showed higher frequencies of sexual behaviors than those in non-PCPA treated ROBN lesion males, but the frequencies were lower than those in PCPA treated non-brain surgery control males. Thus, PCPA may act on serotonergic neurons other than those in the ROBN and facilitate male sexual behaviors in male rats.