Kojima M, Sano Y
Anat Embryol (Berl). 1984;170(2):117-21. doi: 10.1007/BF00318995.
Sexual dimorphism in the topographical organization of immunoreactive serotonergic fibers has been shown for the first time in the anterior column of the rat lumbar cord. A characteristic preferential arrangement of serotonergic fibers on the small cell column composed of anterior horn motoneurons, which have been proved to send their axons to the cremaster muscle, was demonstrated at the lumbar segments (L1-L2) of male rats, using the immunoperoxidase technique with antiserum against serotonin. A similar finding was also observed in female rats, but was less prominent than in males. Comparative analysis of the cell numbers and the size of neuronal somata of the aforementioned nucleus, done using retrograde transport of fluorescent dye (DAPI) via axonal fibers coursing down the genitofemoral nerve to the cremaster muscle, gave significantly larger values in males. The sexual difference in the serotonergic innervation pattern was, in consequence, surmised to be caused by the cytoarchitectonic contrast ascertained in the lumbar anterior column. Furthermore, there may be a striated muscle endowed with some active functions homologous to those of the male cremaster muscle in the female rat.
免疫反应性5-羟色胺能纤维的拓扑组织中的性别二态性首次在大鼠腰髓前柱中被发现。使用抗血清的免疫过氧化物酶技术，在雄性大鼠的腰段（L1-L2），证实了5-羟色胺能纤维在由前角运动神经元组成的小细胞柱上有特征性的优先排列，这些运动神经元已被证明将其轴突发送至提睾肌。在雌性大鼠中也观察到了类似的发现，但不如雄性大鼠明显。通过荧光染料（DAPI）经沿生殖股神经下行至提睾肌的轴突纤维进行逆行运输，对上述核团的细胞数量和神经元胞体大小进行比较分析，结果显示雄性大鼠的值明显更大。因此，推测5-羟色胺能神经支配模式的性别差异是由腰髓前柱中确定的细胞结构差异引起的。此外，雌性大鼠可能存在一种具有与雄性提睾肌某些活跃功能同源的横纹肌。
