The effect of chlorpromazine and dibucaine on phospholipid metabolism in the frog sartorius muscle

Abstract

The effect of cationic amphiphilic drugs, chlorpromazine and dibucaine, on phospholipid metabolism in the frog sartorius muscle was studied at concentrations affecting excitation-contraction coupling. Labelling patterns of phospholipids using 32P orthophosphate were determined. The drugs at a concentration of 3.10(-4) mol/l inhibited the synthesis of phosphatidylcholine and phosphatidylethanolamine and stimulated the synthesis of phosphatidylinositol and phosphatidylserine. At the 3.10(-3) mol/l concentration the drugs blocked the synthesis of all phospholipids without appreciably affecting their degradation. The effect of cationic amphiphilic drugs was independent of the presence of Ca2+ or K+ ions in the media, however, basal labelling of phospholipids was affected by withdrawal of Ca2+ or K+ ions.