CARBON-CENTERED RADICALS REDUCE THE DENSITY OF L-TYPE CALCIUM CHANNELS IN RAT CARDIAC MEMBRANES

The carbon centered radicals generated by preincubation of cumene hydr operoxide with rat cardiac membranes dose dependently reduced the B-ma x of [H-3]nitrendipine binding, while K-D was unchanged. The reduction induced by cumene hydroperoxide was prevented by 2,6-di-t-butlyl-4-me thyl-phenol. The generation of OH did not influence the [H-3]nitrendip ine binding; also other oxidative agents (H2O2 and HClO4) did not modi fy this binding. Therefore the reduction in [H-3]nitrendipine binding sites is not attributable to generic oxidative stress but to the forma tion of carbon centered radicals. (C) 1996 Academic Press, Inc.