CALL FOR PAPERS Mitochondria in Cardiovascular Physiology and Disease Large-conductance Ca2-activated potassium channel in mitochondria of endothelial EA.hy926 cells

Physiol 304: H1415–H1427, 2013. First published March 29, 2013; doi:10.1152/ajpheart.00976.2012.—In the present study, we describe the existence of a large-conductance Ca2-activated potas-sium (BKCa) channel in the mitochondria of the human endothelial cell line EA.hy926. A single-channel current was recorded from endothelial mitoplasts (i.e., inner mitochondrial membrane) using the patch-clamp technique in the mitoplast-attached mode. A potassium-selective current was recorded with a mean conductance equal to 270 10 pS in a symmetrical 150/150 mM KCl isotonic solution. The channel activity, which was determined as the open probability, increased with the addition of calcium ions and the potassium channel opener NS1619. Conversely, the activity of the channel was irrevers-ibly blocked by paxilline and iberiotoxin, BKCa channel inhibitors. The open-state probability was found to be voltage dependent. The substances known to modulate BKCa channel activity influenced th