Effects of platelet-activating factor on single potassium channel currents in guinea pig ventricular myocytes |
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| Authors: | Gordon M. Wahler Dennis E. Coyle Nicholas Sperelakis |
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| Affiliation: | (1) Department of Physiology and Biophysics, University of Cincinnati College of Medicine, 45267-0576 OH, Cincinnati, USA;(2) Department of Anesthesia, University of Cincinnati College of Medicine, 45267-0576 Cincinnati, OH, USA;(3) Department of Physiology and Biophysics, University of Illinois at Chicago, (M/C 901), Box 6998, 60680 Chicago, IL, USA |
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| Abstract: | Platelet-activating factor (PAF) has been implicated as one of the mediators of cardiac anaphylaxis. This phospholipid has been shown to have numerous effects on a variety of tissues, including the heart. Among these effects are alterations in the resting potential and generation of arrhythmias at very low concentrations. This suggests that PAF may modulate the activity of the background, inwardly-rectifying potassium current (IK1). Thus, the effects of PAF on IK1 were examined at the single channel level. Ventricular cells were isolated from adult guinea pig hearts and single channel currents recorded from cell-attached patches. PAF had substantial effects on the single channel currents at sub-nanomolar concentrations (10–11 to 10–10 M). PAF initially caused flickering of the channels, followed by a gradual prolonged depression of channel activity. Since these potassium channels play a major role in determining the resting potential and excitability of the cardiac cell, the effects of PAF on IK1 may play a major role in the deleterious electrophysiological actions of PAF on the heart.Abbreviations IK1 Inwardly-rectifying background potassium current - Lyso-PAF Lyso-platelet-activating factor - PAF Platelet-activating factor |
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| Keywords: | platelet-activating factor potassium channels cardiac electrophysiology |
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