Wahler G M, Coyle D E, Sperelakis N
Department of Physiology and Biophysics, University of Cincinnati College of Medicine, OH 45267-0576.
Mol Cell Biochem. 1990 Mar 5;93(1):69-76. doi: 10.1007/BF00223494.
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.
血小板活化因子（PAF）被认为是心脏过敏反应的介质之一。这种磷脂已被证明对包括心脏在内的多种组织有多种作用。这些作用包括静息电位的改变以及在极低浓度下产生心律失常。这表明PAF可能调节背景内向整流钾电流（IK1）的活性。因此，在单通道水平上研究了PAF对IK1的影响。从成年豚鼠心脏分离出心室细胞，并从细胞贴附膜片记录单通道电流。PAF在亚纳摩尔浓度（10^(-11)至10^(-10) M）时对单通道电流有显著影响。PAF最初引起通道闪烁，随后逐渐导致通道活性的长期抑制。由于这些钾通道在决定心脏细胞的静息电位和兴奋性方面起主要作用，PAF对IK1的影响可能在PAF对心脏的有害电生理作用中起主要作用。
