Local cerebral glucose utilization and local cerebral blood flow in conscious rats after administration of flunarizine.

The effects of the calcium entry blocker flunarizine on physiologic variables, local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were investigated. LCBF and LCGU were determined in 37 anatomically discrete brain regions in lightly restrained, conscious rats, using the quantitative, autoradiographic 14C-iodoantipyrine and 14C-2-deoxyglucose techniques. While 5 mg/kg flunarizine given i.v. did not change any of the measured physiologic variables, flunarizine increased LCBF in nearly all gray matter structures compared with saline-treated controls. LCGU was not changed compared to controls. In control as well as in flunarizine-treated rats coupling between LCGU and LCBF was tight. The ratio of LCBF/LCGU was increased after treatment with flunarizine. The data suggest that under normal physiological conditions the calcium entry blocker flunarizine does not change neuronal activity, but exerts primarily a cerebral vasodilating action.