家兔支配膀胱的传出和传入神经成分在脊髓内的分布——HRP逆行追踪及跨神经节追踪研究

THE INTRASPINAL DISTRIBUTION OF THE NEURONAL ELEMENTS INNERVATING THE BLADDER WALL OF THE RABBIT.A STUDY WITH THE HRP RETROGRADE AND TRANSGANGLIONIC TRACING METHODS

向家兔膀胱壁内注入HRP,通过逆行及跨神经节追踪证明:1.膀胱副交感中枢在S_(2~5)髓节(S_(3、4)为中心),主要位于中间带外侧核(占标记细胞总数78.37%),并由此向网状核、后角外侧缘、侧索、中介核及前角后外侧核内扩散。L_(1~5)也有相当数量的长轴突交感节前神经元被标记,说明膀胱壁内有副交感和交感两种节前神经元分布。2.被标记的初级传入神经元中枢突在骶段人背外侧束,主要沿后角外侧缘呈束状行向网状核和中间带外侧核,大部分终止于此,形成膀胱排尿反射的途径;一部分则更向内侧,在中介核到后连合核处形成终末带。另外还有一小束纤维,沿后角内侧缘向腹侧走行,终止于后连合核。这些核团可能是膀胱意识性感觉的中继处。在L_(2~4)也可见沿后角外侧缘走行终止于网状核、中间带外侧核的纤细纤维束。3.一侧膀胱受脊髓双侧支配,但以同侧为主。

HRP was injected into the wall of urinary bladder in the rabbit and the intraspinal distribution of the afferent and efferent neuronal elements innervating the bladder were examined.The results were as follows:1.The parasympathetic center of the urinary bladder was found in S_(2~5)segments(mainly S_(3~4)),it was located chiefly in the intermediolateral nucleus(78.37%of the total labeled cells were in this nucleus),and from here it extended radially to the reticular nucleus,the lateral border,of the dorsal horn,lateral funiculus,intercalated nucleus,and the dorsolateral nucleus of the ventral horn.A number of labeled sympathetic preganglionic neurons with long axons appeared in L_(1~5)spinal segments,they were located at the same sites as those of thoraco-lumbar sympathetic preganglionic neurons described in literature.These result confirmed that there are two kinds of preganglionic neurons(i.e,parasympathetic and sympathetic)innervating the bladder wall.2.Entering the sacral spinal cord,the labeled central processes of primary afferent neurons of the bladder first appeared in the dorsolateral tract.Most of these fibers ran ventrally along the lateral border of the dorsal horn.Then,they were disseminated to terminate in the reticular nucleus and the intermediolateral nucleus,constituting reflex,pathways.A part of the labeled fibers entered the gray matter of the intermediate zone and terminated in an area extending from the intercalated nucleus to the dorsal commissural nucleus.Additionally,a fine bundle of the labeled primary afferent fibers were observed in the posterior border and medial border of the dorsal horn.They eventually terminated in the dorsal commissural nucleus.These nuclei were thought to be relay stations of the conscious sensory pathway of the bladder.3.Labeled cells and terminals were observed in both sides of the spinal cord even the HRP solution was injected into one side of the bladder wall only.This indicated that each side of the bladder was innervated by two sides of the spinal cord,though mainly by the ipsilateral side.