REGULATION OF GLIBENCLAMIDE RECEPTORS IN CULTURED CHICK CARDIOMYOCYTES

We found that the expression of sulphonylurea receptors which control ATP-dependent potassium channels was up-regulated both by a receptor a gonist and by potassium channel activators. Sulphonylurea receptors de tected on cell membranes of cultured chick cardiomyocytes by [H-3]glib enclamide were increased 2.8-fold following growth of the cells for 1- 2 days in the presence of 30 nM glibenclamide. [H-3]glibenclamide bind ing was also increased similar to 2-fold following growth of the cells in the presence of the ATP-dependent potassium channel activators. pi nacidil, minoxidil and diazoxide, but was diminished to 75% of control following treatment with depolarizing concentrations of KCl. (C) 1995 The Italian Pharmacological Society