雄性大鼠球海绵体肌运动神经元胞体及树突的分布

DISTRIBUTION OF THE CELL BODIES AND DENDRITES OF MOTONEURONS INNERVATING THE BULBOCAVERNOSUS IN MALE RAT

本实验用ＣＢ－ＨＲＰ逆行追踪技术，对１５ 只雄性大鼠（体重２５０～３５０ ｇ）的球海绵体肌运动神经元胞体及树突进行了形态和分布的研究。结果表明：（１）支配大鼠球海绵体肌的神经元主要位于脊髓的Ｌ５ ～Ｓ１ 节段的Ｏｎｕｆ核，大多位于该核的背内侧亚核（ＤＭ ），少量位于背外侧亚核（ＤＬ）。（２）位于背内侧亚核的标记神经元，其树突呈束状，向背侧、背外侧、腹外侧等方向伸延，在其抵止区域可能构成广泛的突触联系。也有向对侧背内侧亚核方向伸延者，可能与双侧肌肉的协调作用有关。另有向前索的白质及软膜下伸延者，可能构成旁侧回路。（３）位于背外侧亚核的标记神经元，其树突主要伸向背内侧亚核，提示可能与其功能的协调有关。

Using the method of CB HRP retrograde tracing, the cell bodies and dendrites of motoneurons innervating the bulbocavernosus of 15 male rats were studied. The results were as follows: (1) The motoneurons innervating the bulbocavernosus were found in Onuf's nucleus of the spinal cord extending between the L5 segment and S1 segment, the majority of which appeared in the dorsomedial subnucleus (DM), and there were some labeled neurons in dorsolateral subnucleus (DL). (2) The dendrites of labeled neurons in DM extended in bundles to dorsal, dorsolateral, ventrolateral, white matter, and formed extensive synaptic connections in these areas; and some of them extended to the DM of opposite side, they might be related to the coordinatim of bilateral muscle actions; and some dendrites extended even to white matter of the anterior column and pia mater. (3) The dendrites of labeled neurons in DL extended to the DM. (Figures 1～4 on plate 55)