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 agonist and by potassium channel activators. Sulphonylurea receptors detected on cell membranes of cultured chick cardiomyocytes by [³H]glibenclamide were increased 2.8-fold following growth of the cells for 1-2 days in the presence of 30 nm glibenclamide. [³H]glibenclamide binding was also increased -2-fold following growth of the cells in the presence of the ATP-dependent potassium channel activators, pinacidil, minoxidil and diazoxide, but was diminished to 75% of control following treatment with depolarizing concentrations of KCI.