Serotonin 1A Receptor Agonist(8 OH DPAT) Reduces Tissue Lesion Volume in the Rat Middle Cerebral Artery Occlusion Model of Ischemia

Abstract

We studied the effectiveness of serotonin la agonist(8 OH DPAT) on the 24 hour ionic lesion volume produced by permanent occlusion of the middle cerebral artery(MCAo) in rats. A 4-hour intravenous infusion of 30pmg/ kg/hr of 8 OH DPAT were given starting at 10 minutes after occlusion. Tissue concentrations of Na, K. and water at infarct and peri-infarct zone were measured by atomic absorption spectroscopy and by wet-dry weight measurements 24 hours after occlusion. Compared with vehicle treatment, 8 OH DPAT treatment reduced tissue water accumulation by 10% and 55% in the frontopyriform cortex(L1) and frontoparietal cortex(L2), sodium accumulation by 20% at L1 and 47% at L2 potassium loss by 24% at L1 and 44% at L2, cell volume fraction loss by 24% at L1 and 47% at L2. Finally the treatment reduced overall lesion volume by about 37%. All these changes were statistically significant at p <0.05. Our findings suggest strongly that 8 OH DPAT is neuroprotective in the rat MCAo model of focal cerebral ischemia.