Both membrane stretch and fatty acids directly activate large conductance Ca(2+)-activated K+ channels in vascular smooth muscle cells

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....

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Bibliographic Details
Published in:FEBS letters 1992-02, Vol.297 (1-2), p.24-28
Main Authors: Kirber, M T, Ordway, R W, Clapp, L H, Walsh, Jr, J V, Singer, J J
Format: Article
Language:English
Subjects:
Animals
Arachidonic Acid - pharmacology
Calcium - metabolism
Cations
Cell Membrane - drug effects
Cell Membrane - physiology
Fatty Acids - pharmacology
Membrane Potentials - drug effects
Muscle, Smooth, Vascular - cytology
Muscle, Smooth, Vascular - drug effects
Muscle, Smooth, Vascular - metabolism
Myristic Acid
Myristic Acids - pharmacology
Potassium Channels - drug effects
Potassium Channels - metabolism
Pulmonary Artery - cytology
Pulmonary Artery - drug effects
Pulmonary Artery - metabolism
Rabbits
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Summary: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.
ISSN:0014-5793
DOI:10.1016/0014-5793(92)80319-C