Modulating effect of calcium activated potassium and chloride channels on detrusor instability / 第三军医大学学报

ABSTRACT

Objective To study the modulation alterations of calcium activated potassium channel (Kca) and calcium activated chloride channels (Clca) on detrusor instability(DI) and their roles in DI. Methods The detrusor instability (DI) animal model was established using female Wistar rats. Detrusor strips were obtained from normal and DI rats. The contraction frequency and amplitude of the strips were measured by an in vitro tension test. The actions of channel openers and blockers were studied. Results Spontaneous contraction frequency and amplitude of DI increased significantly. The block of big conductance calcium activated potassium channel(Bkca) by Iberiotoxin resulted in decrease of frequency but increase of amplitude in the control, but only increase of frequency in DI. The opener, NS1619, resulted in decreases of frequency and amplitude in the control, but only decreases of frequency in DI. The block of small conductance Kca (Skca) by apamin resulted in increases of frequency and amplitude in both control and DI groups, but the opener, Chlorzoxazone, resulted in decreases of frequency and amplitude in the control, but only decrease of frequency in DI. The contraction alterations of DI were significantly lower than those of the control no matter Kca was blocked or opened. NFA, a selective Clca blocker, resulted in no significant frequency and amplitude alteration in the control, but significant decrease in DI. Conclusion These results suggested that Kca and Clca play a critical role in the modulation of detrusor contraction, and the down regulation of Kca and up regulation of Clca suggests that disorder of calcium related regulation may play an important role in DI.