Logotipo do repositório
 

Publicação:
Sodium intake by hyperosmotic rats treated with a GABA(A) receptor agonist into the lateral parabrachial nucleus

Carregando...
Imagem de Miniatura

Orientador

Coorientador

Pós-graduação

Curso de graduação

Título da Revista

ISSN da Revista

Título de Volume

Editor

Elsevier B.V.

Tipo

Artigo

Direito de acesso

Acesso restrito

Resumo

Inhibitory mechanisms in the lateral parabrachial nucleus (LPBN) and central GABAergic mechanisms are involved in the regulation of water and NaCl intake. Besides increasing fluid depletion-induced sodium intake, the activation of GABA(A) receptors with muscimol into the LPBN also induces ingestion of 0.3 M NaCl in normonatremic, euhydrated rats. It has been suggested that inhibitory mechanisms activated by osmotic signals are blocked by GABAA receptor activation in the LPBN, thereby increasing hypertonic NaCl intake. Therefore, in the present study we investigated the effects of muscimol injected into the LPBN on water and 0.3 M NaCl intake in hyperosmotic cell-dehydrated rats (rats treated with an intragastric load of 2 M NaCl). Male Wistar rats with stainless steel cannulas implanted bilaterally into the LPBN were used. In euhydrated rats, muscimol (0.5 nmol/0.2 mu l), bilaterally injected into the LPBN, induced ingestion of 0.3 M NaCl (24.6 +/- 7.9 vs. vehicle: 0.5 +/- 0.3 ml/180 min) and water (6.3 +/- 2.1 vs. vehicle: 0.5 +/- 0.3 ml/180 min). One hour after intragastric 2 M NaCl load (2 ml), bilateral injections of muscimol into the LPBN also induced 0.3 M NaCl intake (22.1 +/- 5.2 vs. vehicle: 0.9 +/- 0.8 ml/210 min) and water intake (16.5 +/- 3.6 vs. vehicle: 7.8 +/- 1.8 ml/210 min). The GABAA antagonist bicuculline (0.4 nmol/0.2 mu l) into the LPBN reduced the effect of muscimol on 0.3 M NaCl intake (7.1 +/- 2.1 ml/210 min). Therefore, the activation of GABAA receptors in the LPBN induces ingestion of 0.3 M NaCl by hyperosmotic cell-dehydrated rats, suggesting that plasma levels of renin or osmolarity do not affect sodium intake after the blockade of LPBN inhibitory mechanisms with muscimol. (c) 2007 Elsevier B.V. All rights reserved.

Descrição

Palavras-chave

Muscimol, sodium appetite, thirst, hypertonicity, osmoreceptor

Idioma

Inglês

Como citar

Brain Research. Amsterdam: Elsevier B.V., v. 1190, p. 86-93, 2008.

Itens relacionados

Financiadores

Unidades

Unidade
Faculdade de Odontologia
FOA
Campus: Araçatuba

Departamentos

Cursos de graduação

Programas de pós-graduação