Yells D P, Hendricks S E, Prendergast M A
Department of Psychiatry, University of Nebraska Medical Center, Omaha.
Brain Res. 1992 Nov 20;596(1-2):73-9. doi: 10.1016/0006-8993(92)91534-l.
We evaluated the effects of bilateral radio-frequency lesions of the paragigantocellular (PGi) reticular nucleus in the ventral medulla on male rat copulatory behavior. In Experiment 1, sexually naive male rats with such lesions were more likely than sham-operated controls to copulate to ejaculation during their first exposure to an estrous female. Additionally, among the rats that copulated to ejaculation, those with lesions demonstrated a reduction in mount frequency (MF), intromission frequency (IF), and ejaculation latency (EL), and an increase in copulatory efficiency (CE). In Expt. 2, sexually experienced male rats were allowed to mate to sexual exhaustion. Males with PGi lesions showed an increased latency to sexual exhaustion and an increased number of ejaculations prior to exhaustion. Additionally, rats with PGi lesions displayed reductions in IF, EL, and post-ejaculatory interval (PEI) as they approached sexual exhaustion. Our results provide further evidence that the PGi is a supraspinal locus of descending inhibitory influence on spinal nuclei mediating ejaculatory reflexes in the male rat.
我们评估了延髓腹侧巨细胞旁网状核（PGi）的双侧射频损伤对雄性大鼠交配行为的影响。在实验1中，与假手术对照组相比，有此类损伤的性幼稚雄性大鼠在首次接触发情雌性时更有可能交配至射精。此外，在交配至射精的大鼠中，有损伤的大鼠表现出爬跨频率（MF）、插入频率（IF）和射精潜伏期（EL）降低，交配效率（CE）提高。在实验2中，让有性经验的雄性大鼠交配至性疲劳。有PGi损伤的雄性大鼠表现出性疲劳潜伏期延长，且在疲劳前射精次数增加。此外，随着接近性疲劳，有PGi损伤的大鼠IF、EL和射精后间隔（PEI）均降低。我们的结果进一步证明，PGi是对介导雄性大鼠射精反射的脊髓核具有下行抑制作用的脊髓上位点。
