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Renal Endothelin Production is Blunted in the Dahl Salt Sensitive Rat
Author(s) -
Speed Joshua S,
Lamarca Babbette,
Fournier Lillian M,
Cockrell Kathy,
Granger Joey P
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.969.21
Subject(s) - endocrinology , medicine , endothelin receptor , chemistry , medullary cavity , endothelin 1 , receptor , sodium , excretion , downregulation and upregulation , kidney , renal medulla , biochemistry , organic chemistry , gene
Although it has been well established that the renal endothelin (ET‐1) system plays an important role in mediating salt excretion under high salt intake through activation of medullary ET‐B receptors, the role of this system in Dahl salt sensitive (DS) hypertension is unclear. The purpose of this study was to determine if the DS rat has abnormalities in the renal medullary endothelin system. The experiment consists of 4 groups, DS rats on low and high Na intakes, and Dahl salt resistant rats (DR) on low and high Na intakes. The results show a slight increase in urinary ET‐1 between the DS rats on low Na (13±2 pg/ml) versus high Na diet (29.8±5.5 pg/ml). Meanwhile, there was a 6‐fold increase in ET‐1 production in the DR rats (17.8±4 pg/ml on low Na diet versus 112±44pg/ml on high Na diet). Medullary ET‐1 production in DR rats on high Na diet was 70.9±5 pg/mg. Interestingly, DS rats produced 50% less medullary ET‐1 compared to DR on high Na (31 ± 2.8 pg/mg). Our results also indicate a downregulation of the ETB receptor in the DS rat (7.7±.8 pg/mg low Na, 2.4±.79 pg/mg high Na), while there is no significant change in arterial pressure after 7 days of a high sodium intake (DS low Na 131±2 mmHg, high Na 138±2 mmHg, DR low Na 135±3 mmHg, high Na 132±2 mmHg). These data indicate that a decrease in medullary ETB receptors and intrarenal production of ET‐1 in the DS rat could play an important role in the development of salt sensitive hypertension in the DS rat.