Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/196826
Type: Artigo de periódico
Title: Altered Renal Sodium Handling In Spontaneously Hypertensive Rats (shr) After Hypertonic Saline Intracerebroventricular Injection: Role Of Renal Nerves.
Author: Guadagnini, Dioze
Gontijo, José Antonio Rocha
Abstract: The mechanism by which blood pressure rises in the SHR strain remains to be elucidated. Also, there is a surprising lack of experimental data on the natriuretic mechanisms induced by intracerebroventricular (ICV) injection of hyperosmotic saline (HoS) in SHR. In normotensive animals ICV injection of HoS causes coordinated responses including natriuresis and inhibition of renal sympathetic nerve activity. In the present study, we hypothesized that presumable blunting of the sympathoinhibitory response to centrally injected HoS may contribute to a lack of suppression of efferent renal nerve outflow in SHR. To test this hypothesis, the present study evaluates the influence of renal denervation after central HoS injection at increasing concentration on urinary sodium handling in SHR compared with age-matched normotensive WKy rats. The study confirmed previous data showing pronounced natriuretic response to centrally HoS stimuli but also demonstrated that the creatinine clearance (C(Cr)) and fractional sodium excretion responses diminished as graded NaCl concentrations were increased in WKy rats but not in SHR. In SHR, increased FE(Na) obtained by central administration of 0.90 M NaCl was produced by increases in proximal (FEP(Na)) and post-proximal fractional urinary sodium rejection without changes in C(Cr), indicating a direct tubular effect. Renal denervation caused significant antinatriuresis by decreased C(Cr) and increased FEP(Na) reabsorption in WKy but not in SHR. This study suggests that natriuresis observed only after higher centrally HoS stimuli with a rightward shift of dose-response curve provides evidence of a down-regulation of target organ responsiveness of periventricular areas of genetic hypertensive rats.
Subject: Animals
Blood Pressure
Creatine
Disease Models, Animal
Dose-response Relationship, Drug
Hypertension
Injections, Intraventricular
Kidney
Male
Natriuresis
Potassium
Rats
Rats, Inbred Shr
Rats, Inbred Wky
Saline Solution, Hypertonic
Sodium
Sympathectomy
Rights: fechado
Identifier DOI: 10.1016/j.lfs.2006.06.005
Address: http://www.ncbi.nlm.nih.gov/pubmed/16806279
Date Issue: 2006
Appears in Collections:Unicamp - Artigos e Outros Documentos

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