Author(s): Castro, L. ; Silva, E. de Castro e ; Lima, A. K. S. ; Souza, F. S. ; Maldonado, I. ; Macêdo, D. F. ; Ferreira, M. G. ; Santamaria, Guillermo Fernandez ; Castro, L. ; Silva, E. de Castro e ; Lima, A. K. S. ; Souza, F. S. ; Maldonado, I. ; Macêdo, D. F. ; Ferreira, M. G. ; Santamaria, Guillermo Fernandez
Date: 2013
Origin: Oasisbr
Subject(s): 5-HT4 receptors; Drinking behavior; Third ventricle injections
Texto completo: acesso restrito. p.443–448
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The aim of the present study was to investigate the effect of acute third ventricle injections of two different 5-HT4 receptor antagonists, GR 113808 and SB 204070, on water intake in different situations. Injections of 80 nmol/rat of both GR 113808 and SB 204070 were unable to modify water intake in normohydrated rats. Pretreatment with GR 113808 (40 and 80 nmol/rat) and SB 204070 (80 and 160 nmol/rat) blunted water intake after third ventricle injections of angiotensin II (9.6 pmol/rat) compared to saline-pretreated controls. Pretreatment with 80 nmol/rat of both antagonists potentiated drinking induced by third ventricle injections of carbachol (11.0 nmol/rat) compared to saline-pretreated control. In all doses employed, none of the compounds was able to modify water intake in dehydrated rats. A separate control test using one-bottle taste aversion paradigm indicated that the reduction in water intake observed in some of the present experiments could not be attributed to a drug-induced malaise. It is suggested that central 5-HT4 receptors exert a dualistic role on the control of water intake potentiating angiotensin II-induced drinking and inhibiting thirst induced by central cholinergic activation.
