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Caffeine Decreases The Expression of Na + /K + ‐Atpase and the Type 3 Na + /H + Exchanger In Rat Kidney
Author(s) -
Lee JongUn,
Ha Jeong Hoon,
Kim Sunmi,
Oh YoonWha,
Kim Soo Wan
Publication year - 2002
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1046/j.1440-1681.2002.03697.x
Subject(s) - chemistry , medicine , western blot , nitric oxide synthase , endocrinology , caffeine , nitric oxide , kidney , atrial natriuretic peptide , aquaporin 1 , messenger rna , nitrite , microbiology and biotechnology , biochemistry , biology , nitrate , water channel , engineering , inlet , gene , mechanical engineering , organic chemistry
SUMMARY 1. The aim of the present study was to explore the mechanisms underlying the renal effects of caffeine. 2. Male Sprague‐Dawley rats were treated with caffeine, consisting of a single oral bolus (0.2%, 20 mL/kg) followed by supplementation in drinking water (0.2%) for 1 day. Rats treated the same but given water without caffeine served as controls. 3. The expression of α 1‐ and β 1‐subunits of Na + /K + ‐ATPase, the type 3 Na + /H + exchanger (NHE3) and aquaporin‐1 was determined in the kidney by western blot analysis. 4. To explore possible involvement of local humoral mediators, the tissue expression of nitric oxide synthase (NOS) proteins was determined by western blot analysis and the expression of atrial natriuretic peptide (ANP) mRNA was determined by semiquantitative reverse transcription–polymerase chain reaction. 5. Following treatment with caffeine, the expression of α 1‐ and β 1‐subunits of Na + /K + ‐ATPase, as well as that of NHE3, was decreased. Accordingly, the catalytic activity of Na + /K + ‐ATPase was decreased. In contrast, the expression of aquaporin‐1 was not altered significantly. 6. The expression of the endothelial isoform of NOS was increased, along with tissue nitrite/nitrate levels. The expression of ANP mRNA was increased. 7. It is suggested that caffeine decreases Na + /K + ‐ATPase and NHE3 activities and increases nitric oxide and ANP activities in the kidney.