Hindbrain serotonin and the rapid induction of sodium appetite
Nenhuma Miniatura disponível
Data
2000-07-01
Autores
Menani, José Vanderlei [UNESP]
De Luca, L. A.
Thunhorst, R. L.
Johnson, A. K.
Título da Revista
ISSN da Revista
Título de Volume
Editor
Amer Physiological Soc
Resumo
Both systemically administered furosemide and isoproterenol produce water intake (i.e., thirst). Curiously, however, in light of the endocrine and hemodynamic effects produced by these treatments, they are remarkably ineffective in eliciting intake of hypertonic saline solutions (i.e., operationally defined as sodium appetite). Recent work indicates that bilateral injections of the serotonin receptor antagonist methysergide into the lateral parabrachial nuclei (LPBN) markedly enhance a preexisting sodium appetite. The present studies establish that a de novo sodium appetite can be induced with LPBN-methysergide treatment under experimental conditions in which only water is typically ingested. The effects of bilateral LPBN injections of methysergide were studied on the intake of water and 0.3 M NaCl following acute (beginning 1 h after treatment) diuretic (furosemide)-induced sodium and water depletion and following subcutaneous isoproterenol treatment. With vehicle injected into the LPBN, furosemide treatment and isoproterenol injection both caused water drinking but essentially no intake of hypertonic saline. In contrast, bilateral treatment of the LPBN with methysergide induced the intake of 0.3 M NaCl after subcutaneous furosemide and isoproterenol. Water intake induced by subcutaneous furosemide or isoproterenol was not changed by LPBN-methysergide injections. The results indicate that blockade of LPBN-serotonin receptors produces a marked intake of hypertonic NaCl (i.e., a de novo sodium appetite) after furosemide treatment as well as subcutaneous isoproterenol.
Descrição
Palavras-chave
furosemide, sodium intake, water intake, 5-hydroxytryptamine
Como citar
American Journal of Physiology-regulatory Integrative and Comparative Physiology. Bethesda: Amer Physiological Soc, v. 279, n. 1, p. R126-R131, 2000.