Polymorphonuclear leukocyte as a model of Ca++ and Mg++-dependent cellular activation. Effect of flunarizine.

Flunarizine, a calcium entry blocker drug, concentration-dependently inhibited FMLP and A23187-induced aggregation, enzyme release and superoxide anion generation from human granulocytes. A23187-dependent granulocyte aggregation was also studied in media devoided of Ca++ or Mg++. Flunarizine (2.4 x 10(-5) M) significantly affected not only Ca++-supported but also Mg++-sustained granulocyte aggregation. The inhibiting effect of the drug was reversed by increasing extracellular level of Ca++ (1.2 mM) or Mg++ (2 mM). In this "in vitro" model, the role of flunarizine as a specific Mg++ entry blocker was suggested.