In vitro effects of flunarizine on human lymphocytes

Flunarizine, a slow-channel calcium entry blocker used as a vasodilator, interferes in vitro with human lymphocyte functions. It prevents lymphocytes from capping sheep erythrocytes, an effect which is probably due to the disconnection of the membrane from its cytoskeletal control. Flunarizine antagonizes both colchicine and cytochalasin B effects upon capping. Although the mitogen-induced lymphocyte stimulation has been shown to be sensitive to calcium depletion or calcium entry blocking by Verapamil, an enhanced response to phytohaemagglutinin A was observed with flunarizine. This suggests a differential sensitivity of the lymphocytes to calcium-entry blockers.