THE THERAPEUTIC VALUE OF NALOXONE AND MANNITOL IN EXPERIMENTAL FOCAL CEREBRAL-ISCHEMIA - NEUROLOGICAL OUTCOME, HISTOPATHOLOGICAL FINDINGS, AND TISSUE CONCENTRATIONS OF NA+, K+ AND WATER

In this study, the effect of naloxone and mannitol was investigated on focal cerebral ischemia induced by middle cerebral artery occlusion w ith the transorbital approach in the rabbit model. Rabbits were random ly and blindly assigned to one of three groups (six animals in each): (1) a control group that received equal volumes of physiological salin e solution; (2) a naloxone group that received a 5 mg/kg bolus of nalo xone i.v. 1 h after occlusion, followed by 2 mg/kg per hour i.v. infus ion for 5 h; (3) a mannitol group that received 0.2 g/kg twice with an interval of 10 min at 5 h. The neurological outcome was better in rab bits treated with naloxone than in the others. The ratio of ischemic t o total neurons in the cortex was smaller in the naloxone group than i n the control and mannitol groups (P<0.05). In addition, there was a s tatistically significance reduction in infarct size in the naloxone gr oup compared with the other groups (P<0.05). Edema was severe in the c ontrol and mannitol groups, but moderate in the naloxone group. There was no statistically significant difference in Na+, K+, and water cont ent between groups. Our data provide evidence for the beneficial effec ts of naloxone on promoting neurological recovery and preserving the i schemic area.