人工体神经-内脏神经反射弧的神经电生理研究

目的从电生理学角度研究躯体运动神经能否再生替代内脏运动神经及再生神经的电生理性质,探讨新反射弧支配膀胱的可能机制。方法显微吻合大鼠左侧L4L6前根建立控制排尿的人工体神经-内脏神经反射弧,电刺激吻合口近端,记录盆神经节前、节后纤维的诱发电位和膀胱压力变化,使用特异性神经节受体阻断剂六烃季铵观察节后纤维诱发电位和膀胱压力的变化,刺激同侧坐骨神经观察的膀胱压力变化;以正常鼠为对照组。结果1．刺激吻合口近端,吻合口远端盆神经、盆神经节后神经纤维均可记录到诱发电位,并可引起膀胱收缩;2．刺激吻合神经同侧坐骨神经可记录到膀胱压的升高;3．六烃季胺可阻止盆神经节的讯号传导;4．人工反射弧再生的传出神经较对照具有更快的传导速度。结论躯体运动神经与内脏运动神经吻合后,体神经运动神经轴突可以再生替代内脏运动神经,并通过盆神经节支配膀胱逼尿肌。

An electrophysiological study on the artificial somato-autonomic pathway for inducing voiding

OBJECTIVE: To investigate the possibility of regeneration of somatic motor nerve to replace splanchnic nerve and the electrophysiologic characters of the regenerated nerve. METHODS: An artificial somato-autonomic reflex pathway was established by intradural microanastomosis of L(4) ventral root (VR) to L(6)VR at the left side in 12 male Wistar rats. Then the L(4)VR proximal to the anastomosis was stimulated by silver electrode and the evoked potentials were recorded on the distal end to the anastomosis, pelvic nerve and postganlionic fibers of the major pelvic ganglia (MPG). Cystometrography was used to record the intravesical pressure. Hexamethonium, a cholinergic ganglion blocker, was given directly on the pelvic ganglion so as to observe the change of the intravesical pressure evoked by stimulation of the nerves. Another 12 rats were used as controls. RESULTS: (1) In the experimental group, stimulation of the L(4)VR proximal end to the anastomosis evoked potentials on the distal end, the pelvic nerve, and the postganglionic fibers of the MPG, and induced bladder contraction. Stimulation of the contralateral sciatic nerve failed to evoke change of intravesical pressure. In the control group stimulation of the L(4)VR or sciatic nerve failed to evoke potentials on the postganglionic fibers of pelvic nerve and change of intravesical pressure. (2) Stimulation of the ipsilateral sciatic nerve led to an increase of intravesical pressure. (3) After the use of hexamethonium stimulation of the ipsilateral sciatic nerve and proximal end of L(4)-L(6) anastomosis failed to evoke change of intravesical pressure. (4) The conduction velocity of the regenerated motor axons was 33.3 m/s +/- 6.9m/s, significantly higher than that of the control group (11.6 m/s +/- 1.6 m/s). CONCLUSION: Somatic motor axons can regenerate to the MPG and reinnervate the bladder and the impulses from the somatic motor neurons can initiate voiding.