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High salt intake increases ET B receptor function in the renal medulla of rats
Author(s) -
Jin Chunhua,
Pollock David M.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.lb836
Subject(s) - endocrinology , renal medulla , medicine , chemistry , diuretic , excretion , kidney , renal function , diuresis , perfusion
The present study was conducted to test the hypothesis that high salt intake would increase the diuretic and natriuretic effects of renal medullary ET B receptor stimulation in vivo. Two groups of male Sprague Dawley (SD) rats were compared; after being fed normal (0.3%) and high salt (4%) diet for 7 days. Rats were anesthetized and a catheter implanted in the renal medulla for interstitial infusion along with a ureteral catheter for urine collection. An adjustable occluder was placed around the aorta proximal to the left renal artery to maintain renal perfusion pressure throughout the protocol. After equilibration and two 20 min control periods, the urine flow (UV) and sodium excretion (UNaV) responses to medullary infusion of a low dose of the ET B receptor agonist sarafotoxin S6c (0.15 μg/kg/h) were determined over an 80 min infusion period. Intramedullary infusion of a relatively low dose of S6c (0.15 μg/kg/h) markedly increased the urine flow and sodium excretion in the high salt treated rats (UV: 5.6±0.7 to 30.7±3.1 μl/min; UNaV: 1.1±0.2 to 2.2±0.3 μmol/min; n=9), but not in the normal salt treated rats (UV: 8.6±2 to 11.6±1.9 μl/min; UNaV 0.5±0.1 to 0.5±0.1 μmol/min; n=8). We conclude that high salt intake enhances the diuretic and natriuretic effects of ET B receptor stimulation in vivo consistent with a role for the ET B receptor in maintaining fluid‐electrolyte balance.