Stretch activation of a toad smooth muscle K+ channel may be mediated by fatty acids
Graduate School of Biomedical Sciences; Department of Physiology
Medical Subject Headings
Albumins; Animals; Bufo marinus; Fatty Acids; Membrane Potentials; Muscle, Smooth; Myristic Acid; Myristic Acids; Patch-Clamp Techniques; Physical Stimulation; Potassium Channels; Time Factors
Life Sciences | Medicine and Health Sciences
1. using standard single channel patch clamp techniques we studied the stretch sensitivity of a 20 pS K(+)-selective channel which is activated by fatty acids and found in freshly dissociated smooth muscle cells from the stomach of the toad Bufo marinus. 2. A pulse of suction applied to the back of the patch pipette in order to stretch the membrane resulted in activation of this K+ channel. A train of suction pulses resulted in a gradually increased level of channel activity during each successive pulse, as well as an increase in baseline activity between pulses. This pattern contrasts markedly with many other stretch-activated channels whose activation is limited to the duration of the suction pulse. 3. Application of fatty acids augmented the response to stretch. In contrast, application of 10 microM defatted albumin, which removes fatty acids from membranes, rapidly and reversibly decreased the response to stretch. 4. These results are consistent with the hypothesis that fatty acids which are generated by mechanical stimuli, perhaps by mechanically activated phospholipases, are the intermediaries in activation of certain mechanically sensitive ion channels.
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Citation: J Physiol. 1995 Apr 15;484 ( Pt 2):331-7.
The Journal of physiology
Ordway, Richard W.; Petrou, Steven; Kirber, Michael T.; Walsh, John V.; and Singer, Joshua J., "Stretch activation of a toad smooth muscle K+ channel may be mediated by fatty acids" (1995). GSBS Student Publications. 922.