CONTINUOUS NIMODIPINE TREATMENT ATTENUATES CORTICAL INFARCTION IN RATS SUBJECTED TO 24 HOURS OF FOCAL CEREBRAL-ISCHEMIA

Focal cerebral infarction and edema were measured in rats (Wistar, Fisher 344, and spontaneously hypertensive strains) pretreated with nimodipine (2 μg/kg/min i.v.) or its vehicle and subjected to the tandem occlusion of the middle cerebral and common carotid arteries. Animals awoke from anesthesia 10-15 min after onset of ischemia and continued to receive treatment over a 24-h survival period. Cortical infarction and edema were quantified by image analysis of frozen brain sections processed for histology. Nimodipine-treated rats developed 20-60% smaller cortical infarct volumes than con-trois (p < 0.002). Cortical edema was reduced proportionately to the decrease in infarct volume and constituted ∼36% of the infarct volume. Nimodipine caused a mild hypotensive response that did not aggravate ischemic brain damage. The results indicate that continuous nimodipine treatment, started before induction of focal cerebral ischemia, can attenuate ischemic brain damage and edema as late as 24 h after the onset of ischemia.