Flunarizine, a Calcium Entry Blocker, Ameliorates Ischemic Brain Damage in the Rat

Abstract

The effects of flunarizine, a calcium entry blocker, were evaluated in a long-term survival model of ischemia in rats. One group of animals received the drug orally at 24 and 4 h prior to the insult (40 mg .cntdot. kg-1 .cntdot. dose-1). Another group was given flunarizine following the insult, intravenously at 5 min (0.1 mg .cntdot. kg-1), and orally at 8 and 24 h (40 mg .cntdot. kg-1 .cntdot. dose-1). A third group received the solvent for the oral suspension on the same schedule as the pretreated group. Six animals from each group were subjected to 9 min ischemia and recovery of 7 days, at which time the brains were harvested for histologic study. In another six animals from each group, cortical metabolites and fatty acids were determined during early recirculation. Local cerebral blood flow was measured at 60 min recirculation in a third set of animals. Flunarizine significantly improved histological outcome (fewer irreversibly damaged cells) in both treatment groups. This amelioration was not related to improvement of cerebral blood flow during the period of delayed hypoperfusionn nor the postischemic levels of high-energy phosphates or free fatty acids.