辣椒素对慢性脊髓损伤大鼠排尿功能的影响

目的：明确辣椒素对正常大鼠和慢性脊髓损伤(SCI)大鼠排尿功能的影响和作用的可能机制。方法：建立SCI的动物模型，实验大鼠和正常大鼠分别全身给药或膀胱内灌注辣椒素，记录膀胱内压力变化图(CMG)和尿道外括约肌肌电图(EUS-EMG)的改变。结果：正常大鼠辣椒素全身用药后出现非排尿性膀胱收缩，排尿效率下降，但排尿压不受影响。膀胱内灌注辣椒素亦会导致排尿效率降低而不影响排尿压。SCI大鼠全身用药后非排尿性膀胱收缩消失，残余尿量减少，排尿压下降，但排尿效率提高，膀胱内用药则可完全阻断排尿反射。结论：对辣椒素敏感的膀胱感觉传入神经参与正常大鼠和SCI大鼠的排尿反射。对正常大鼠起稳定膀胱逼尿肌的作用，而对SCI大鼠则是引起膀胱灌注时非排尿性收缩的原因，因此，阻滞感觉传入神经纤维是治疗SCI后膀胱高反射的有效方法。

Effect of capsaicin on micturition in chronic spinal male rats

Objective: To compare normal rat and rat with chronic spinal cord injury (SCI) with CMG and EUS after intravesical capsaicin or given s.c to determine the role of capsaicin-sensitive bladder afferents in micturition. Methods: Male Sprague-Dawley rats, normal or with spinal cord transection at the level of T 9-10 . CMG and EUS-EMG tests were carried out before and after administration of capsaicin intravesically or s.c 8 weeks after SCI. Results: Capsaicin given subcutaneously induced the nonvoiding bladder contractions in normal rats. After administration rats had large voiding volume(VV) and residual volme (RV) ,voiding efficiency(VE) was decreased ,but micturing press(MP) was not affected. Intravesical capsaicin also decreased VE with the MP non affected. In SCI rats the nonvoiding bladder contractions induced by infusion of saline before voiding can be eliminated by capsaicin (125 mg/kg s.c) .But intravesical capsaicin can inhibit the reflex bladder contraction in SCI rats. Conclusion: The data indicated the capsaicin sensitive bladder afferents take part in the initiation of reflex micturition in both normal and SCI rats .In normal rats activity in the capsaicin sensitive fibers initiated by bladder filling keep the compliance of bladder .In SCI rats these afferents do contribute to hyperactivity of the bladder during the filling phase of the CMG.