화학공학소재연구정보센터
Biochemical and Biophysical Research Communications, Vol.358, No.1, 311-316, 2007
Hypoxia increases BK channel activity in the inner mitochondrial membrane
To explore the potential function of the BK channel in the inner mitochondrial membrane under physiological and hypoxic conditions, we used on-mitoplast and whole-mitoplast patches. Single BK channels had a conductance of 276 +/- 9 pS under symmetrical K+ solutions, were Ca2+-and volt age-dependent and were inhibited by 0.1 mu M charybdotoxin. In response to hypoxia, BK increased open probability, shifted its reversal potential (9.3 +/- 2.4 mV) in the positive direction and did not change its conductance. We conclude that (1) the properties at rest of this mitoplast K+ channel are similar to those of BK channels in the plasma membrane; (2) hypoxia induces an increase, rather than a decrease (as in the plasmalemma), in the open probability of this K+ channel, leading to K+ efflux from the mitochondrial matrix to the outside. We speculate that this increase in K+ efflux from mitochondria into the cytosol is important during hypoxia in maintaining cytosolic K+. (c) 2007 Elsevier Inc. All rights reserved.