Activation of Background Membrane Conductance by the Tyrosine Kinase Inhibitor Tyrphostin A23 and Its Inactive Analog Tyrphostin A1 in Guinea Pig Ventricular Myocytes

[摘要] References(15)The effects of the tyrosine kinase (TK) inhibitor tyrphostin A23 and its inactive analog tyrphostin A1 on background membrane conductance were investigated in guinea pig ventricular myocytes. TK-inhibiting A23 reversibly increased membrane conductance under conditions designed to minimize Na+, Ca2+, K+, and Na+-K+ pump currents. Similar stimulatory action was obtained with TK-inactive A1. The tyrphostin-induced current was inhibited by omitting external Na+ or Ca2+, suppressed by chelating internal Ca2+, blocked by external Cd2+ and Ni2+, and insensitive to changes in internal Cl− concentration. We conclude that tyrphostins have a direct, TK-independent action that increases membrane conductance probably by stimulating Na+-Ca 2+ exchange.

[学科分类] 药理学

[关键词] Tyrphostin;Tyrosine kinase;Na+-Ca2+ exchange