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Id: |
lil-414720
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Autor: |
Cavalcante-Lima, H. R; Badauê-Passos Júnior, D; De-lucca Júnior, W; Lima, H. R. C; Costa-e-Sousa, R. H; Olivares, E. L; Cedraz-Mercez, P. L; Reis, R. O; Medeiros, M. A; Côrtes, W. S; Reis, L. C. |
Título: |
Chronic excitotoxic lesion of the dorsal raphe nucleus induces sodium appetite |
Fonte: |
Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;38(11):1669-1675, Nov. 2005. ilus.
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Idioma: |
en.
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Projeto: |
Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro.
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Resumo: |
We determined if the dorsal raphe nucleus (DRN) exerts tonic control of basal and stimulated sodium and water intake. Male Wistar rats weighing 300-350 g were microinjected with phosphate buffer (PB-DRN, N = 11) or 1 æg/0.2 æl, in a single dose, ibotenic acid (IBO-DRN, N = 9 to 10) through a guide cannula into the DRN and were observed for 21 days in order to measure basal sodium appetite and water intake and in the following situations: furosemide-induced sodium depletion (20 mg/kg, sc, 24 h before the experiment) and a low dose of dietary captopril (1 mg/g chow). From the 6th day after ibotenic acid injection IBO-DRN rats showed an increase in sodium appetite (12.0 ± 2.3 to 22.3 ± 4.6 ml 0.3 M NaCl intake) whereas PB-DRN did not exceed 2 ml (P < 0.001). Water intake was comparable in both groups. In addition to a higher dipsogenic response, sodium-depleted IBO-DRN animals displayed an increase of 0.3 M NaCl intake compared to PB-DRN (37.4 ± 3.8 vs 21.6 ± 3.9 ml 300 min after fluid offer, P < 0.001). Captopril added to chow caused an increase of 0.3 M NaCl intake during the first 2 days (IBO-DRN, 33.8 ± 4.3 and 32.5 ± 3.4 ml on day 1 and day 2, respectively, vs 20.2 ± 2.8 ml on day 0, P < 0.001). These data support the view that DRN, probably via ascending serotonergic system, tonically modulates sodium appetite under basal and sodium depletion conditions and/or after an increase in peripheral or brain angiotensin II.
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Descritores: |
Ácido Ibotênico/toxicidade Agonistas de Aminoácidos Excitatórios/toxicidade Apetite/efeitos dos fármacos Ingestão de Líquidos/efeitos dos fármacos Núcleos da Rafe/efeitos dos fármacos Sódio na Dieta
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-Apetite/fisiologia Tampões (Química) Captopril/farmacologia Furosemida/farmacologia Ingestão de Líquidos/fisiologia Inibidores da Enzima Conversora de Angiotensina/farmacologia Inibidores de Simportadores de Cloreto de Sódio e Potássio/farmacologia Fosfatos Ratos Wistar Fatores de Tempo
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Limites: |
Animais Masculino Ratos
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Responsável: |
BR1.1 - BIREME
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