A study of the excitatory spinal reflex pathway related to the bladder contraction in cats.

脑桥排尿中心对排尿收缩至关重要。盆腔神经膀胱分支受到其他膀胱分支刺激后的反射放电也被认为是通过该中枢引起的。目前的研究集中在是否有一个骶骨反射中心，这是最近没有考虑到的。所有实验均切除两侧胃下神经。(1)脊髓横断后出现的振幅小、间隔相对较快的收缩-松弛波动依赖于膀胱内压力，在膀胱内压力100-150 mmH20左右出现最大振幅（80-100 mmH20）。在切除脊髓后，这些波动急剧减少（10-30 mmH20），这表明波动是由脊髓反射和神经节反射引起的。(2)在分离盆腔神经两条膀胱神经分支间的所有侧支的条件下，电刺激一条膀胱分支引起另一条膀胱分支早反射（20-40 ms）和晚反射（约100 ms）。当用玻璃微电极记录骶部副交感神经节前神经元时，盆腔神经膀胱分支的刺激也引起了早期（14-26 ms）和晚期（62-106 ms）的反射。两种制剂中早期反射的潜伏期表明这是通过脊髓引起的。早期和晚期反射之间的放电减少，从细胞内研究表明，这是由ipsp引起的。排尿收缩时的早期反射比膀胱放松时更大，说明早期反射与长时反射类似，依赖于膀胱活动。

The pontine micturition centre is essential for the micturition contraction. Reflex discharges in the bladder branch of the pelvic nerve after stimulation of other bladder branch are also thought to be evoked via this centre. The present study focuses on whether there is a sacral reflex centre that has not recently been considered. The hypogastric nerves of both sides were cut in all experiments. (1) Contraction-relaxation fluctuations with small amplitudes and relatively fast intervals observed after transection of the spinal cord were dependent on the intravesical pressure, showing maximal amplitudes (80-100 mmH20) at around 100-150 mmH20 of the intravesical pressure. After removal of the spinal cord, these fluctuations dramatically reduced (10-30 mmH20), suggesting that the fluctuations were evoked by a spinal reflex as well as by a ganglion reflex. (2) In preparations where all collaterals between the two bladder nerve branches of the pelvic nerve were split, electrical stimulation of one bladder branch evoked early (20-40 ms) and late (around 100 ms) reflexes on the other bladder branch. When recording from the sacral parasympathetic preganglionic neurones with a glass microelectrode, stimulation of the bladder branch of the pelvic nerve also evoked early (14-26 ms) and late (62-106 ms) reflexes. The latency of the early reflex in both preparations indicated that this was evoked via the spinal cord. Firings between the early and late reflex were reduced, suggesting that, from the intracellular study, it was caused by IPSPs. The early reflex was larger during micturition contraction than when the bladder was relaxed, indicating that the early reflex was dependent on the bladder activity similar to the long reflex.