E Prostanoid-1 receptor regulates renal medullary alphaENaC in rats infused with angiotensin II.
E Prostanoid (EP) receptors play an important role in urinary Na(+) excretion. In the kidney, the epithelial sodium channel (ENaC) is the rate-limiting-step for Na(+) reabsorption. We hypothesized that activation of EP1/EP3 regulates the expression of ENaC in the face of renin-angiotensin-aldosterone-system (RAAS) activation. In primary cultures of inner medullary collecting duct (IMCD) cells, sulprostone (EP1>EP3 agonist, 1 microM) and 17 Phenyl trinor (17 Pt, EP1 agonist, 10 microM) prevented the up-regulation of alphaENaC mRNA induced by aldosterone (10 nM). In Sprague-Dawley rats infused with angiotensin II (0.4 microg/kg/min), alphaENaC expression was up-regulated in renal cortex and medulla coincidently with high plasma aldosterone levels. Sulprostone and/or 17 Pt prevented this effect in renal medulla but not in cortex. Immunocytochemistry demonstrated that IMCD cells express EP1. Our results suggest that specific activation of EP1 receptor during RAAS activation antagonizes the action of aldosterone on alphaENaC expression in the renal medulla.
González
Alexis A
AA
Departamento de Fisiología, Center for Aging and Regeneration, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile. aagonzap@uc.cl
Céspedes
Carlos
C
Villanueva
Sandra
S
Michea
Luis
L
Vio
Carlos P
CP
D000450:Aldosterone / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D015232:Dinoprostone / Q000031:analogs & derivatives / Q000494:pharmacology; D053503:Epithelial Sodium Channels / Q000378:metabolism*; D007679:Kidney Medulla / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018078:Receptors, Prostaglandin E / Q000235:genetics / Q000378:metabolism*; D058306:Receptors, Prostaglandin E, EP1 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D012084:Renin-Angiotensin System / Q000187:drug effects
D053503:Epithelial Sodium Channels; C545637:Ptger1 protein, rat; C545649:Ptger3 protein, rat; D018078:Receptors, Prostaglandin E; D058306:Receptors, Prostaglandin E, EP1 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; C440894:Scnn1a protein, rat; D000804:Angiotensin II; D000450:Aldosterone; C016767:sulprostone; D015232:Dinoprostone