Enhanced Atrial Natriuretic Peptide and Nitric Oxide System Following the Treatment with Caffeine in Rats / 대한신장학회잡지

ABSTRACT

PURPOSE: The present study was aimed to examine whether caffeine alters the local regulation of atrial natriuretic peptide(ANP) and nitric oxide(NO) systems in the kidney. METHODS: Male Sprague-Dawley rats were treated with caffeine, consisting of a single oral bolus(0.2%, 1 mL/kg) followed by supplementation in drinking water(0.2%) for 1 day. Rats treated the same without caffeine served as control. The tissue expression of ANP mRNA was determined by reverse transcription-polymerase chain reaction. Tissue levels of nitrite/nitrate were determined. The expression of aquaporin(AQP)-1 and AQP2 proteins was determined by Western blot analysis. RESULTS: Following the treatment with caffeine, the expression of ANP mRNA was increased in the kidney. The renal tissue nitrite/nitrate level was also increased by caffeine-treatment. On the other hand, the expression of AQP1 and AQP2 proteins was not significantly altered. CONCLUSION: The enhanced activities of local ANP and NO systems may in part be causally related with the caffeine-induced natriuresis and diuresis, while AQP channels are not involved.