Effect of Losartan on renin-angiotensin system in brain of SHR / 中国药理学通报

ABSTRACT

AIM To discuss the effects of losartan on AT 1R mRNA expression and renin angio tensin system (RAS) level in brain of spontaneously hypertensive rat (SHR). METHODS Sixteen 6 week old male SHR and 16 sex and age matched WKY were divided into losartan ( n =8) and control groups ( n =8) respectively. Losartan (30 mg?kg -1 ?d -1 ) or equal volume of 0.9% saline solution was administered for 18 weeks by gavage. AT 1R mRNA expression was examined by reverse transcription polymerase chain reaction (RT PCR). Renin activity (RA) and angiotensinⅡ(AngⅡ) levels were measured by radio immunoassay. Angiotensin converting enzyme activity (ACEA) was measured by ultraviolet spectrophotometar. RESULTS Enhanced brain AT 1R mRNA expression was found in SHR compared with WKY ( P 0.05, respectively). CONCLUSION The increase of AT 1R mRNA expression and RAS levels in brain may be involved in the pathogenesis of hypertension in SHR. Losartan protects brain by decreasing expression of brain AT 1R mRNA.