Lesions of the commissural subnucleus of the nucleus of the solitary tract increase isoproterenol-induced water intake

Autor(es)

G.T. Blanch ^[1] ; A.H. Freiria-Oliveira ^[2] ; E. Colombari ; J.V. Menani ^[4] ; D.S.A. Colombari ^[5]

Afiliação do(s) autor(es)

^[1] Universidade Estadual Paulista. Faculdade de Odontologia. Departamento de Fisiologia e Patologia - Brasil

^[2] Universidade Estadual Paulista. Faculdade de Odontologia. Departamento de Fisiologia e Patologia - Brasil

^[4] Universidade Estadual Paulista. Faculdade de Odontologia. Departamento de Fisiologia e Patologia - Brasil

^[5] Universidade Estadual Paulista. Faculdade de Odontologia. Departamento de Fisiologia e Patologia - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 40, n. 8, p. 1121-1127, 2007-07-05.

Resumo

The nucleus of the solitary tract (NTS) is the primary site of the cardiovascular afferent information about arterial blood pressure and volume. The NTS projects to areas in the central nervous system involved in cardiovascular regulation and hydroelectrolyte balance, such as the anteroventral third ventricle region and the lateral parabrachial nucleus. The aim of the present study was to investigate the effects of electrolytic lesion of the commissural NTS on water and 0.3 M NaCl intake and the cardiovascular responses to subcutaneous injection of isoproterenol. Male Holtzman rats weighing 280 to 320 g were submitted to sham lesion or electrolytic lesion of the commissural NTS (N = 6-15/group). The sham-lesioned rats had the electrode placed along the same coordinates, except that no current was passed. Water intake induced by subcutaneous isoproterenol (30 µg/kg body weight) significantly increased in chronic (15 days) commissural NTS-lesioned rats (to 2.4 ± 0.2 vs sham: 1.9 ± 0.2 mL 100 g body weight-1 60 min-1). Isoproterenol did not induce any sodium intake in sham or in commissural NTS-lesioned rats. The isoproterenol-induced hypotension (sham: -27 ± 4 vs commissural NTS-lesioned rats: -22 ± 4 mmHg/20 min) and tachycardia (sham: 168 ± 10 vs commissural NTS: 144 ± 24 bpm/20 min) were not different between groups. The present results suggest that the commissural NTS is part of an inhibitory neural pathway involved in the control of water intake induced by subcutaneous isoproterenol, and that the overdrinking observed in lesioned rats is not the result of a cardiovascular imbalance in these animals. (AU)

• Processo FAPESP: 03/05275-6 - Efeitos da lesao do nucleo do trato solitario comissural sobre a ingestao de agua e sodio e sobre os efeitos cardiovasculares induzidos pela sobrecarga de sodio.
• Beneficiário: Graziela Torres Blanch
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 03/08768-3 - Estudo dos efeitos hemodinamicos e sobre o comportamento ingestivo apos a desconexao hipotalamica em ratos normotensos e hipertensos.
• Beneficiário: Débora Simões de Almeida Colombari
• Modalidade de apoio: Auxílio à Pesquisa - Regular