Holmes G M, Rogers R C, Bresnahan J C, Beattie M S
Department of Cell Biology, Neurobiology and Anatomy, Ohio State University, Columbus 43210, USA.
Physiol Behav. 1997 Jan;61(1):57-63. doi: 10.1016/s0031-9384(96)00317-4.
The effects of thyrotropin-releasing hormone (TRH) on the sexual and defecatory reflexes regulated by pudendal motoneurons were investigated. Intrathecal TRH (10 microliters volume; 0.0, 0.01, 1.0 or 100 microM concentration) at lumbosacral spinal segments (L4-S1) in acute preparations produced a dose-dependent increase in external anal sphincter (EAS), but not bulbospongiosus (BS), electromyographic (EMG) activity. Intraspinal (L6) injection of 100 microM TRH (1 microliter/micropipette), significantly increased EAS EMG activity in acute preparations. Electromyographic activity of the BS muscle was unchanged. All doses of intrathecal TRH (10 microliters volume; 0, 10, 50, 100, or 500 microM concentration) in awake animals significantly reduced the proportion of responders to a penile reflex test. Subsequently, all measures of penile reflexes were significantly reduced. Glans tumescence and defecation bouts before or during penile reflex testing were unaffected by intrathecal TRH as were indices of behavioral and motor hyper-reactivity analogous to that produced by serotonin. These data indicate that pudendal motoneurons, in the dorsomedial nucleus, are differentially regulated by neuropeptides present in the lumbosacral spinal cord.
研究了促甲状腺激素释放激素（TRH）对由阴部运动神经元调节的性反射和排便反射的影响。在急性制备的腰段脊髓节段（L4-S1）给予鞘内注射TRH（体积10微升；浓度0.0、0.01、1.0或100微摩尔/升），可使肛门外括约肌（EAS）的肌电图（EMG）活动呈剂量依赖性增加，但球海绵体肌（BS）的EMG活动无变化。在急性制备中，脊髓内（L6）注射100微摩尔/升TRH（1微升/微量移液器）可显著增加EAS的EMG活动，而BS肌的EMG活动未改变。在清醒动物中，所有剂量的鞘内注射TRH（体积10微升；浓度0、10、50、100或500微摩尔/升）均显著降低阴茎反射试验的反应者比例，随后阴茎反射的所有指标均显著降低。阴茎反射测试前或测试期间的龟头肿胀和排便次数不受鞘内注射TRH的影响，类似于血清素产生的行为和运动性高反应性指标也不受影响。这些数据表明，位于背内侧核的阴部运动神经元受腰段脊髓中存在的神经肽的差异性调节。
