目的 观察5-羟色胺（5-HT）对膀胱传入神经自发放电活动和机械敏感性的影响。方法 采用离体大鼠膀胱—盆神经标本，观察膀胱腔内给予不同浓度5-HT后，盆神经自发放电频率及充胀膀胱引起的放电活动的变化。结果 膀胱未充胀时，盆神经仅有少量自发放电活动（<10 imp/s）；充胀时，盆神经放电频率随膀胱内压力递增而升高；膀胱腔内给予5-HT （1～30 μmol/L, 0.1 mL）后，盆神经自发放电频率呈剂量依赖性增加，对0～15 mmHg范围（低压区）充胀刺激的反应增强。结论 5-HT能直接激活膀胱低阈值传入神经，并增强其对机械刺激的反应。

Objective To investigate the effect of 5-hydroxytryptamine (5-HT) on the spontaneous and mechanosensitive activity of bladder afferent nerves. Methods The effects of intravesical instillation of different concentrations of 5-HT on the spontaneous and distension-induced pelvic afferent nerve activity were observed in the isolated rat bladder/pelvic nerve preparations. Results At rest, with the bladder empty, there was little background activity (<10 imp/s) in the pelvic nerve branch innervating the bladder. During ramp distension, the afferent nerve activity increased progressively as the intravesical pressure rose. Intraluminal instillation of 0.1 mL 5-HT (1 to 30 μmol/L) caused an increase of the ongoing afferent discharge and potentiated the low threshold (0-15 mmHg) mechanosensory responses in a concentration-dependent manner. Conclusion 5-HT directly activates low threshold bladder afferent fibers in the pelvic nerve, and can potentiate their mechanosensitivity.