大鼠下尿路、腰骶髓脊髓排尿中枢逆行神经追踪研究

Retrograde neural tracing of the lumbar-sacral spinal cord micturition center

目的应用荧光金(FG)、快蓝(FB)、辣根过氧化物酶(HRP)逆行神经追踪技术研究盆神经节(MPG)、尿道外括约肌(EUS)与骶髓排尿中枢之间的神经通路。方法选用正常雄性SD大鼠,盆神经节、尿道外括约肌、尿道黏膜下、膀胱逼尿肌内注射神经追踪剂组织化学反应及荧光显微镜。结果标记神经元在脊髓L6部至S1侧角(以L6多见)可见FB阳性神经元,L6脊髓前角的腹外侧部,即Onuf’s核,同时中间外侧柱(IML)、中央管周围出现FG阳性神经元。盆神经节在荧光显微镜下可发现HRP暗黑色阳性神经细胞和呈蓝色的荧光阳性神经细胞;脊髓L6部至S1灰质后联合核、中央管周围I、ML区同时出现FG、FB细胞,但未发现FG、FB的双标细胞。结论大鼠脊髓内排尿中枢主要位于脊髓L6-S1节段,主要包括支配盆神经节的PGN和支配EUS的前角神经元。灰质后联合核、中央管周围I、ML区内的亦可见少许神经元。盆神经节支配膀胱逼尿肌,是排尿反射的最后一级神经元。

Objective To study the morphology of the spinal micturition center by retrograde tracing with HRP, FG and FB. Methods In normal male Sprague-Dawley rats, HRP, FG and FB were injected into MPG, EUS, urethra and bladder. Sections were stained histochemieally and observed under fluorescence microscopy. Results FB labeled neurons were observed in the L6-S1 intermediolateral nucleus （IML）. FG labeled neurons were observed in the L6-S1 ventrolateral portion （Onuf＇s nucleus）, and also in IML, dorsal gray commissure （DGC）, and periaqueduetal gray. There were many HRP labeled neurons and FB labeled neurons in the same field in MPG. No double labeled neuron was found. FG labeled neurons and FB labeled neurons were observed in the same visual field in IML, DGC, periaqueduetal gray of the lumbar-sacral segments of the spinal cord, but no double positive neurons were found. Conclusion The L6-S1 segments of the rat host the major neurons for mieturition reflex in different areas. The postganglionic neurons in the major pelvic ganglion may also take part in the coordination of the bladder and the urethra in addition to their well known innervation of the detrusor.