BK通道对大鼠膀胱Cajal间质细胞兴奋性的调控作用

BK channels regulate function of interstitial cells of Cajal in rat bladder

目的观察BK通道在大鼠膀胱Cajal间质细胞(interstitial cells of Cajal,ICCs)中的表达,探讨其对膀胱ICCs的调节功能。方法健康雌性清洁SD大鼠48只,Western blot和免疫荧光双标观测膀胱ICCs BK通道表达情况,膜片钳记录膀胱ICCs BK通道电流,激光共聚焦检测膀胱ICCs钙内流。结果膀胱ICCs表达起主要功能的BK通道α、β1亚基,记录到ICCs上BK通道外向电流。通道特异性阻断剂蝎毒素(IBTX)可明显抑制膀胱ICCs细胞BK电流,+80 mV下药物作用后相对电流由(23.627±3.897)pA降低为(3.603±1.885)pA(P<0.05)。IBTX可增加膀胱ICCs钙离子内流,胞内钙荧光强度(F1/F0)从(1.00±0.07)增加到(1.84±0.45),(P<0.05)。结论膀胱ICCs表达BK通道,阻断BK通道可增加膀胱ICCs的兴奋性。

Objective To investigate the expression and function of large conductance calcium-activated potassium （BK） channels in rat bladder interstitial cells of Cajal （ICCs）. Methods Forty-eight SD rats were used in this study. The expression of the BK channels in the ICCs was detected by double-labeled fluorescence analysis and Western blotting. The BK channel function in the ICCs was assessed using confocal microscopy. The currents of BK channels were evaluated using the whole-cell patch clamp technique, with or without the treatment of selective BK inhibitor iberiotoxin （IBTX）. Results The ot and 131 subunits of the BK channel were expressed on the membrane of bladder ICCs. IBTX decreased the currents of BK channels and increased calcium influx in the ICCs apparently （ P 〈 0. 05 ）. Conclusion BK channels are expressed in rat bladder ICCs. Blocking BK channels increases the excitability of ICCs of rat bladder.