DO L-ARGININE AND L-NAME ALTER CORONARY VASCULAR AND AORTIC ENDOTHELIAL PERMEABILITY IN NORMAL- AND HIGH-CHOLESTEROL-FED RATS?

Abstract    INTRODUCTION: The objective of this study was to evaluate the effect of L-arginine (L-Arg) and L-NAME on coronary vascular and aortic endothelial permeability in normocholesterolemic (NC) and hypercholesterolemic (HC) rats.    METHODS: Forty-eight male rats were divided into NC and HC groups and each group was divided into L-Arginine-treated, L-NAME-treated and control subgroups. L-Arg (۲.۲۵%) and L-NAME (۰.۷۵ mg/ml) were dissolved in drinking water and control groups received tap water. After ۸ weeks, endothelial permeability was assessed by using the Evans Blue (EB) dye method.    RESULTS: Aortic endothelial permeability was significantly higher in HC group compared to NC group (۱۵.۱±۰.۷ vs. ۷.۷±۰.۸ µgEB/g tissue, respectively; P<۰.۰۵). L-Arg and L-NAME treatment decreased aortic endothelial permeability in HC animals (L-Arg: ۸.۴±۰.۴ & L-NAME: ۱۰.۸±۰.۶ vs. ۱۵.۱±۰.۷ µgEB/g tissue, respectively; P<۰.۰۵). There was no significant difference in endothelial permeability in coronary circulation between HC and NC groups and L-Arg and L-NAME did not alter endothelial permeability.    CONCLUSION: It seems that L-Arg and L-NAME have different effects on endothelial permeability based on physiological and pathological conditions and type of vessel.         Keywords: L-Arginine, L-NAME, nitric oxide, endothelium, permeability.