Renal sympathoinhibition induced by hypernatremia: involvement of A1 noradrenergic neurons

Renal sympathoinhibition induced by hypernatremia: involvement of A1 noradrenergic neurons

Autor Pedrino, Gustavo Rodrigues Autor UNIFESP Google Scholar
Rosa, Daniel Alves Autor UNIFESP Google Scholar
Korim, Willian Seiji Autor UNIFESP Google Scholar
Cravo, Sergio Luiz Autor UNIFESP Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
Resumo Several findings suggest that A1 noradrenergic neurons in the caudal ventrolateral medulla (CVLM) contribute to body fluid homeostasis and cardiovascular regulation. Recently we demonstrated that the renal vasodilation induced by infusion of hypertonic saline (HS) depends on the integrity of the A1 neurons. Here we determined the effect of lesions of these neurons on the inhibition of the renal sympathetic nerve activity (RSNA) induced by HS infusion. All experiments were performed in Wistar rats (280-350 g). A1 neurons were lesioned by microinjections of antidopamine-beta-hydroxylase-saporin (6.3 ng in 60 nl) into the CVLM (n=5), whereas sham rats received microinjections of free saporin (1.3 ng in 60 nl, H=10). Two weeks later, rats were anesthetized (urethane 1.2 g/kg, iv), and instrumented for recording of arterial pressure and RSNA. in sham rats, HS infusion (3 M NaCl, 0.18 ml/100 g bw, iv) induced a transient (<= 30 min) hypertension (peak at 10 min; 9 5 mm Hg) and a fall in RSNA (-32 +/- 7% of baseline at 10 min). A1-lesions increased the duration of the pressor response induced by HS infusion (16 +/- 2 mm Hg at 60 min) and abolished the fall in RSNA (-6 +/- 8% of baseline at 10 min). Catecholaminergic lesions extensions were confirmed by immunocytochemistry. Unilateral renal denervation reduced the renal vasodilatation induced by HS infusion (112 +/- 7% in denervated rats versus 127 +/- 4% in sham, 20 min after HS). These results Suggest that A1 noradrenergic neurons are involved in the sympathoinhibition and consequent renal vasodilatation to acute changes in the extracellular fluid compartment. (C) 2008 Elsevier B.V. All rights reserved.
Palavra-chave A1 noradrenergic neurons
Renal sympathetic nerve activity
Renal denervation
Arterial blood pressure
Hypertonic saline
Caudal ventrolateral medulla (CVLM)
Idioma Inglês
Financiador Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Número do financiamento CAPES: BEX1380/07-9
Data de publicação 2008-11-03
Publicado em Autonomic Neuroscience-basic & Clinical. Amsterdam: Elsevier B.V., v. 142, n. 1-2, p. 55-63, 2008.
ISSN 1566-0702 (Sherpa/Romeo, fator de impacto)
Publicador Elsevier B.V.
Extensão 55-63
Fonte http://dx.doi.org/10.1016/j.autneu.2008.06.006
Direito de acesso Acesso restrito
Tipo Artigo
Web of Science WOS:000260905000011
Endereço permanente http://repositorio.unifesp.br/handle/11600/31030

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