Premium
Natriuretic activity of prehypertensive Dahl salt‐sensitive (DS) and salt‐resistant (SS13BN) rats
Author(s) -
Nakano Daisuke,
Middleton Christopher L.,
Socha Heather M.,
Boesen Erika I.,
Pollock David M.
Publication year - 2008
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.22.1_supplement.1158.4
Subject(s) - natriuresis , endocrinology , medicine , excretion , chemistry , agonist , sodium , renal medulla , receptor , diuretic , epithelial sodium channel , blood pressure , kidney , organic chemistry
We have recently demonstrated that activation of the ET B receptor in the renal medulla induces a natriuretic response in anesthetized rats and that sodium excretion of an acute salt load in the conscious rat requires the ET B receptor. We hypothesized that animals genetically susceptible to salt‐induced hypertension (DS) would have reduced ET B ‐mediated natriuresis compared to salt‐resistant controls (SS13BN). Therefore, the aims of the current studies were to determine the natriuretic response to 1) intramedullary ET B activation and 2) an acute oral salt load in DS and SS13BN rats. Sarafotoxin 6c (S6c; 1–10 pmol/kg/min; n = 6), a selective ET B agonist, infused into the renal medullary interstitium dose‐dependently increased the sodium excretion without affecting systemic blood pressure, although no difference was observed in the response between DS and SS13BN (10 pmol/kg/min; 2.3 ± 0.2 μmol/min and 2.0 ± 0.3 μmol/min, respectively). In a separate series of experiments, conscious rats received an acute salt challenge of 900 μEq Na p.o. Both strains exhibited significant sodium excretion within the first 12 hours post challenge (DS: 1.48 ± 0.13 mEq; SS13BN: 1.68 ± 0.11 mEq). Again, there was no difference between the strains. In conclusion, these studies suggest that acute ET B ‐dependent natriuretic mechanisms are intact in both salt‐resistant and salt‐sensitive strains of rats.