Both membrane stretch and fatty acids directly activate large conductance Ca2+‐activated K+ channels in vascular smooth muscle cells

作者：Michael T. Kirber, Richard W. Ordway, Lucie H. Clapp, John V. Walsh, Joshua J. Singer · 发表于：FEBS Letters · 年份：1992 · DOI：10.1016/0014-5793(92)80319-c · 被引用次数：204 · 研究领域：Ion channel regulation and function、Cardiac electrophysiology and arrhythmias、Nitric Oxide and Endothelin Effects

Large conductance Ca(2+)-activated K+ channels in rabbit pulmonary artery smooth muscle cells are activated by membrane stretch and by arachidonic acid and other fatty acids. Activation by stretch appears to occur by a direct effect of stretch on the channel itself or a closely associated component. In excised inside-out patches stretch activation was seen under conditions which precluded possible mechanisms involving cytosolic factors, release of Ca2+ from intracellular stores, or stretch induced transmembrane flux of Ca2+ or other ions potentially capable of activating the channel. Fatty acids also directly activate this channel. Like stretch activation, fatty acid activation occurs in excised inside-out patches in the absence of cytosolic constituents. Moreover, the channel is activated by fatty acids which, unlike arachidonic acid, are not substrates for the cyclo-oxygenase or lypoxygenase pathways, indicating that oxygenated metabolites do not mediate the response. Thus, four distinct types of stimuli (cytosolic Ca2+, membrane potential, membrane stretch, and fatty acids) can directly affect the activity of this channel.