Effects of platelet activating factor on action potentials and potassium channels in guinea-pig ventricular myocytes

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Journal Title:
ACTA PHYSIOLOGICA SINICA
Issue:
Volume 56, Issue 03, 2004
DOI:
Key Word:
platelet activating factor;cardiac myocyte;action potential;potassium channels;patch clamp technique

Abstract: This study was designed to investigate the effects of platelet activating factor (PAF) on the action potential and potassium currents in guinea-pig ventricular myocytes. Whole cell patch clamp techniques were used. With 5 mmol/L ATP in the pipette electrode (mimic normal condition), 1 μmol/L PAF increased APD90 from 225.8±23.3 to 352.8±29.8 ms (n=5, P<0.05), decreased IK1 and IK tail currents from -6.1±1.3 to -5.6±1.1 nA (n=5, P<0.05) at -120 mV and from 173.5±16.7 to 152.1±11.5 pA (P<0.05, n=4) at +30 mV,respectively. But PAF had no effect on IK1 at potentials within the normal range of membrane potentials (between -90 mV and +20 mV).restore prolongation of APD induced by PAF. In conclusion, in guinea-pig ventricular myocytes, with 5 mmol/L ATP in the pipette PAF hence a decrease in APD. It is suggested that PAF may amplify the heterogeneity between ischemic and normal cardiac myocytes during ischemia/reperfusion, which may play a vital role in the pathogenesis of the arrhythmias induced by ischemia/reperfusion.

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