Potassium channel KV alpha1 subunit expression and function in human detrusor muscle.

Abstract

We determined whether voltage gated K+ (KV) channels are expressed and functional in human detrusor smooth muscle Information on KV channels was obtained using electrophysiological patch clamp, immunofluorescence, Western blot and isometric tension recording techniques Patch clamp recordings from detrusor cells revealed a Ca2+ independent K+ current that was activated by depolarization in a voltage range near the resting potential of detrusor smooth muscle. The current was inhibited by 3,4-diaminopyridine, a blocker of KV channels. Antibodies targeted to KValpha1 subunits revealed KV1.3 and KV1.6 expression in whole bladder tissue samples and specifically in detrusor smooth muscle cells. New specific blockers of KValpha1 channel currents (correolide and recombinant agitoxin-2) had a myogenic effect, characterized by increased amplitude of spontaneous contractions without an effect on the frequency of contractions or on resting baseline tension. KValpha1 subunits are expressed and functionally important in human detrusor muscle.