Cerebral infarction in the Mongolian gerbil exacerbated by phenoxybenzamine treatment.

Abstract

In a double-bline study, the effects of a large dose (20 mg/kg) and a small dose (2 mg/kg) of phenoxybenzamine (PBZ) on cerebral infarction were evaluated in 120 Mongolian gerbils [Meriones unguiculatus]. The left common carotid artery was ligated in 100 animals; a sham operation was done in 20 animals. One hour later, 25 animals were given 2 mg/kg of PBZ, 25 animals were given 20 mg/kg of phenoxybenzamine, and 50 animals were given 0.5 cc of normal saline, all doses being repeated at 24, 48 and 72 h. Five sham-operated animals were given 2 mg/kg of phenoxybenzamine, 5 were given 20 mg/kg of phenoxybenzamine and 10 were given 0.5 cc of normal saline on the same treatment schedule. Morbidity and mortality were recorded for 1 wk and then all surviving animals were killed. All brains were studied for signs of infarction. Of the saline-treated animals, 32% had cerebral infarction and 81% of these died. Of the animals treated with phenoxybenzamine, 36% of those receiving 2 mg/kg and 68% (P. < 0.05) of those receiving 20 mg/kg had cerebral infarction and all of those with infarction died during the observation period. The animals receiving phenoxybenzamine had a larger stroke index than those treated with saline. Phenoxybenzamine is harmful is postischemic treatment of strokes.