Nimodipine posttreatment does not increase blood flow in rats with focal cortical ischemia

Abstract

We used laser-Doppler fiowmetry to study the effect of nimodipine administered after the onset of focal cortical ischemia on regional cerebral blood flow in 16 halothane-anesthetized, mechanically ventilated Wistar rats. We selected the Wistar rat strain since it would provide a wide range of ischemia severities to test the vascular response to nimodipine. laser-Doppler probes continuously recorded regional cerebral blood flow at two or three sites over the parietal cortex (dura intact) while brain temperature was regulated at 37° C. Occlusion of the right middle cerebral and common carotid arteries reduced cerebral blood flow to a mean of 38% (range 13-77%) of baseline. Thirty minutes later, either 2/ig/kg/min nimodipine (n=8) or its vehicle, polyethylene glycol 400 (n =8), was administered by a continuous intravenous infusion. Over 60 minutes of treatment, both the nimodipine-treated and vehicle-treated groups showed a trivial (3%) mean increase in cerebral blood flow. Nimodipine failed to augment cerebral blood flow regardless of whether the cortex was severely, moderately, or mildly ischemic. © 1990 American Heart Association, Inc.