Aprindine

Aprindine is an Ib-class anti-arrhythmic agent. Aprindine mainly exerts its effect by blocking sodium channels (I_Na), thereby reducing the excitability and conduction velocity of cardiac muscle cells. Aprindine significantly inhibits delayed potassium currents, which helps to prolong the atrial effective refractory period (AERP) and inhibit the occurrence of atrial fibrillation. Aprindine can also regulate intracellular calcium ion concentration by inhibiting Na⁺/Ca²⁺ exchange current (INCX), thereby further stabilizing cardiac electrical activity. Aprindine can be used for the study of atrial fibrillation (AF) and ventricular arrhythmias^{[1][2][3][4][5]}. In Vitro:Aprindine (0-128 μg/mL, 1 h-7 d) inhibits the proliferation of bone marrow cells and human lymphocytes with ED₅₀s of 15.5 μg/mL and 8 μg/mL, and also inhibits the colony formation of normal human bone marrow CFU-C cells^[1].
Aprindine (0-1000 μM) exhibits concentration-dependent inhibition on Na⁺/Ca²⁺ exchange current (INCX), and the inhibitory effects on both inward (IC₅₀ = 51.8 μM, -100mV) and outward (IC₅₀ = 48.8 μM, 50 mV) currents are similar, suggesting no significant voltage dependence in CCL39 cells^[2].
Aprindine (0-40 μM) competes with KB-R7943 (HY-138947) and inhibits extracellular Ca²⁺ in CCL39 cells^[2].
Aprindine (3 μM) significantly inhibits voltage-dependently rectifier K⁺ current (I_k), and has a slight effect on I_ca and inward rectifier K⁺ current (I_k1) in guinea pig atrial muscle cells^[3].
Aprindine (0-100 μM) inhibits the acetylcholine receptor-operated K⁺ current (I_k.Ach) induced by Carbachol (HY-B1208) and GTPγS (HY-137677B) with the IC₅₀ values of 0.4 and 2.5 mM, respectively in guinea pig atrial muscle cells^[3].
Aprindine (3 μM) inhibits the induction of atrial fibrillation (AF) by prolonging monophasic action potential (MAP) and effective refractory period (ERP) in isolated guinea pig heart^[3].
Aprindine (0-500 μM) inhibits the calcium-binding protein-activated phosphodiesterase and Ca-ATPase activities in both isolated bovine brain tissue and human red blood cells with the IC₅₀ values of 18 and 84 μM, respectively^[4].
In Vivo:Aprindine (5 mg/kg, i.v., single dose) demonstrates a significant anti-arrhythmic effect in the Warfarin (HY-B0687) induced arrhythmia model of guinea pigs, suggesting its remarkable sodium channel-blocking property^[5].