Effects of central imidazolinergic and alpha2-adrenergic activation on water intake

• Autor(a) principal: Sugawara, A. M. [UNESP]
• Data de Publicação: 2001
• Outros Autores: Miguel, T. T. [UNESP], Pereira, D. T. B. [UNESP], Menani, José Vanderlei [UNESP], Luca Junior, Laurival Antonio de [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1590/S0100-879X2001000900012; http://hdl.handle.net/11449/16178
• topic: imidazolines; agmatine; UK 14304; guanabenz; alpha-methylnoradrenaline; thirst; dehydration

Non-adrenergic ligands that bind to imidazoline receptors (I-R), a selective ligand that binds to alpha2-adrenoceptors (alpha2-AR) and mixed ligands that bind to both receptors were tested for their action on water intake behavior of 24-h water-deprived rats. All drugs were injected into the third cerebral ventricle. Except for agmatine (80 nmol), mixed ligands binding to I-R/alpha2-AR such as guanabenz (40 nmol) and UK 14304 (20 nmol) inhibited water intake by 65% and up to 95%, respectively. The selective non-imidazoline alpha2-AR agonist, alpha-methylnoradrenaline, produced inhibition of water intake similar to that obtained with guanabenz, but at higher doses (80 nmol). The non-adrenergic I-R ligands histamine (160 nmol, mixed histaminergic and imidazoline ligand) and imidazole-4-acetic acid (80 nmol, imidazoline ligand) did not alter water intake. The results show that selective, non-imidazoline alpha2-AR activation suppresses water intake, and suggest that the action on imidazoline sites by non-adrenergic ligands is not sufficient to inhibit water intake.