Muscarinic agonists inhibit the ATP-dependent potassium current and suppress the ventricle–Purkinje action potential dispersion

Activation of the parasympathetic nervous system has been reported to have an antiarrhythmic role during ischemia–reperfusion injury by decreasing arrhythmia triggers. Furthermore, it was that neurotransmitter acetylcholine is able modulate ATP-dependent potassium current (I K-ATP ), a crucial activated hypoxia. However, possible significance this modulation in mechanism not fully clarified. Action potentials were measured using conventional microelectrode technique from canine left ventricular papillary muscle and free-running Purkinje fibers, under normal hypoxic conditions. Ionic currents whole-cell configuration patch-clamp method. Acetylcholine at 5 ?mol/L did influence action potential duration (APD) either fibers or preparations. In contrast, significantly lengthened APD suppressed Purkinje–ventricle dispersion when administered after pinacidil application. Carbachol 3 reduced pinacidil-activated I voltage-clamp simulated ischemia condition. study, we found inhibits thus suppresses ventricle–Purkinje dispersion. We conclude tone may reduce arrhythmogenic substrate exerting complex