[beta ]-adrenergic stimulation modulates the sodium current block by propafenone in rat ventricular myocardium☆

摘要: Abstract Propafenone is a class I antiarrhythmic drug used to suppress cardiac arrhythmia both of atrial and ventricular origin. We measured fast sodium current (I Na +) directly with the loose-patch-clamp technique confirme frequency-dependent block this current. Effects on steady-state kinetics were small or even in opposite direction. Since propafenone interacts [beta ]-adrenergic receptor stimulation itself increases +, was combined isoproterenol (100 nmol/L). Now we found an augmentation +. Together ]-receptor antagonist atenolol, exhibited more potency but only slightly increased. conclude that effect predomantly due phosphorylation channel not displacement from ]-receptor. Nevertheless, clinical settings various states sympathetic tone one has be aware different effects.