AIM:To investigate the effects of ketamine anesthesia on the motility alterations and tissue injury caused by ischemia/reperfusion in rats.METHODS:Thirty maIe Wistar rats weighing 200-250 g were used.Ischemia was induced by obstructing blood flow in 25% of the total small intestinal length(ileum)with a vascular clamp for 45 min,after which either 60 min or 24 h of reperfusion was allowed.Rats were either anesthetized with pento-barbital sodium(50 mg/kg)or ketamine(100 mg/kg).Control groups received sham surgery,After 60 min of reperfusion,the intestine was examined for mor-phological alterations,and after 24 h intestinal basic electrical rhythm(BER)frequency was calculated,and intestinal transit determined in all groups.RESULTS:The intestinal mucosa in rats that were anesthetized with ketamine showed moderate alterations such as epithelial lifting,while ulceration and hemorrhage was observed in rats that received pento-barbital sodium after 60 min of reperfusion.Quantitative analysis of structural damage using the Chiu scale showed significantly Iess injury in rats that received ketamine than in rats that did not(2.35±1.14 vs 4.58 ±0.50,P＜0.0001).The distance traveled by a marker,expressed as percentage of total intestinal length,in rats that received pentobarbital sodium was 20% ± 2% in comparison with 25.9% ±1.64% in rats that received ketamine(P=0.017).BER was not statistically different between groups.CONCLUSION:Our results show that ketamine anesthesia is associated with diminished intestinal iniury and abolishes the intestinal transit delay induced by ischemia/reperfusion.(C)2008 The WJG Press.All rights reserved.