Referenced in: none

Automatically associated channels: Kv2.1

Title: ATP inhibits smooth muscle Ca2(+)-activated K+ channels.

Authors: C H Gelband, S D Silberberg, K Groschner, C Van Breemen

Journal, date & volume: Proc. Biol. Sci., 1990 Oct 22 , 242, 23-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/1980739

Abstract
There has been much recent interest in the roles played by smooth-muscle K+ channels in protecting cells against ischemic and anoxic insults and in therapeutic vaso- and bronchodilation (Buckingham 1990; Longmore & Weston 1990). A K+ channel, which is uniquely sensitive to cytoplasmic ATP (KATP), has been identified as a likely candidate for mediating these important functions (Standen et al. 1989). We now show, by using electrophysiological techniques in three different types of smooth muscle, that a large-conductance voltage and Ca2(+)-sensitive channel, otherwise indistinguishable from the the large-conductance Ca2(+)-activated K+ channel (BK channel), is also sensitive to cytoplasmic ATP and cromakalim. ATP, in a dose-dependent manner, decreased the probability of channel opening (Po) of rabbit aortic, rabbit tracheal and pig coronary artery BK channels with a Ki of 0.2-0.6 mM. Cromakalim, 10 microM, partially reversed the ATP induced inhibition and increased Po. Our observations raise the possibility that the ubiquitous BK channel may play a role during pathophysiological events.