Sengelaub Dale R, Forger Nancy G
Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA.
Horm Behav. 2008 May;53(5):596-612. doi: 10.1016/j.yhbeh.2007.11.008. Epub 2007 Nov 28.
Cell number in the spinal nucleus of the bulbocavernosus (SNB) of rats was the first neural sex difference shown to differentiate under the control of androgens, acting via classical intracellular androgen receptors. SNB motoneurons reside in the lumbar spinal cord and innervate striated muscles involved in copulation, including the bulbocavernosus (BC) and levator ani (LA). SNB cells are much larger and more numerous in males than in females, and the BC/LA target muscles are reduced or absent in females. The relative simplicity of this neuromuscular system has allowed for considerable progress in pinpointing sites of hormone action, and identifying the cellular bases for androgenic effects. It is now clear that androgens act at virtually every level of the SNB system, in development and throughout adult life. In this review we focus on effects of androgens on developmental cell death of SNB motoneurons and BC/LA muscles; the establishment and maintenance of SNB motoneuron soma size and dendritic length; BC/LA muscle morphology and physiology; and behaviors controlled by the SNB system. We also describe new data on neurotherapeutic effects of androgens on SNB motoneurons after injury in adulthood.
大鼠球海绵体肌脊髓核（SNB）中的细胞数量是首个被证明在经典细胞内雄激素受体介导的雄激素控制下发生分化的神经性别差异。SNB运动神经元位于腰脊髓，支配参与交配的横纹肌，包括球海绵体肌（BC）和肛提肌（LA）。雄性SNB细胞比雌性大得多且数量更多，雌性的BC/LA靶肌肉减少或缺失。这个神经肌肉系统相对简单，使得在确定激素作用位点以及确定雄激素作用的细胞基础方面取得了相当大的进展。现在很清楚，雄激素在SNB系统的几乎每个层面都有作用，无论是在发育过程中还是在整个成年期。在这篇综述中，我们重点关注雄激素对SNB运动神经元和BC/LA肌肉发育性细胞死亡的影响；SNB运动神经元胞体大小和树突长度的建立和维持；BC/LA肌肉的形态和生理；以及由SNB系统控制的行为。我们还描述了雄激素对成年期损伤后SNB运动神经元的神经治疗作用的新数据。
