A1 Noradrenergic Neurons Lesions Reduce Natriuresis and Hypertensive Responses to Hypernatremia in Rats

A1 Noradrenergic Neurons Lesions Reduce Natriuresis and Hypertensive Responses to Hypernatremia in Rats

Author Silva, Elaine Fernanda da Google Scholar
Freiria-Oliveira, Andre Henrique Google Scholar
Xavier Custodio, Carlos Henrique Google Scholar
Ghedini, Paulo Cesar Google Scholar
Mendes Bataus, Luiz Artur Google Scholar
Colombari, Eduardo Google Scholar
Castro, Carlos Henrique de Google Scholar
Colugnati, Diego Basile Autor UNIFESP Google Scholar
Rosa, Daniel Alves Google Scholar
Cravo, Sergio Luiz Autor UNIFESP Google Scholar
Pedrino, Gustavo Rodrigues Google Scholar
Institution Universidade Federal de Goiás (UFG)
São Paulo State Univ
Universidade Federal de São Paulo (UNIFESP)
Abstract Noradrenergic neurons in the caudal ventrolateral medulla (CVLM; A1 group) contribute to cardiovascular regulation. the present study assessed whether specific lesions in the A1 group altered the cardiovascular responses that were evoked by hypertonic saline (HS) infusion in non-anesthetized rats. Male Wistar rats (280-340 g) received nanoinjections of antidopamine-beta-hydroxylase-saporin (A1 lesion, 0.105 ng.nL(-1)) or free saporin (sham, 0.021 ng.nL(-1)) into their CVLMs. Two weeks later, the rats were anesthetized (2% halothane in O-2) and their femoral artery and vein were catheterized and led to exit subcutaneously between the scapulae. On the following day, the animals were submitted to HS infusion (3 M NaCl, 1.8 ml . kg(-1), b.wt., for longer than 1 min). in the sham-group (n = 8), HS induced a sustained pressor response (Delta MAP: 35 +/- 3.6 and 11 +/- 1.8 mmHg, for 10 and 90 min after HS infusion, respectively; P<0.05 vs. baseline). Ten min after HS infusion, the pressor responses of the anti-D beta H-saporin-treated rats (n = 11) were significantly smaller(Delta MAP: 18 +/- 1.4 mmHg; P<0.05 vs. baseline and vs. sham group), and at 90 min, their blood pressures reached baseline values (2 +/- 1.6 mmHg). Compared to the sham group, the natriuresis that was induced by HS was reduced in the lesioned group 60 min after the challenge (19 +/- 65.5 mM vs. 262 +/- 7.6 mM, respectively; P<0.05). in addition, A1-lesioned rats excreted only 47% of their sodium 90 min after HS infusion, while sham animals excreted 80% of their sodium. Immunohistochemical analysis confirmed a substantial destruction of the A1 cell group in the CVLM of rats that had been nanoinjected withanti-D beta H-saporin. These results suggest that medullary noradrenergic A1 neurons are involved in the excitatory neural pathway that regulates hypertensive and natriuretic responses to acute changes in the composition of body fluid.
Language English
Sponsor Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundacao de Amparo a Pesquisa do Estado de Goias (FAPEG)
Grant number CNPq: 477832/2010-5
CNPq: 483411/2012-4
Fundacao de Amparo a Pesquisa do Estado de Goias (FAPEG): 200910267000352
Date 2013-09-10
Published in Plos One. San Francisco: Public Library Science, v. 8, n. 9, 11 p., 2013.
ISSN 1932-6203 (Sherpa/Romeo, impact factor)
Publisher Public Library Science
Extent 11
Origin http://dx.doi.org/10.1371/journal.pone.0073187
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000327538600019
URI http://repositorio.unifesp.br/handle/11600/36750

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