Mineralocorticoid modulation of central angiotensin-induced neuronal activity, water intake and sodium appetite



Título del documento: Mineralocorticoid modulation of central angiotensin-induced neuronal activity, water intake and sodium appetite
Revista: Brazilian journal of medical and biological research
Base de datos: PERIÓDICA
Número de sistema: 000350347
ISSN: 0100-879X
Autores: 1
1
1
Instituciones: 1Universite Henri Poincare-Nancy I, Faculte de Medecine, Nancy, Meurthe-et-Moselle. Francia
Año:
Periodo: May
Volumen: 40
Número: 5
Paginación: 699-705
País: Brasil
Idioma: Inglés
Tipo de documento: Artículo
Enfoque: Experimental, aplicado
Resumen en inglés Central angiotensin II (AngII) stimulates water and salt solution intake. Pretreatment with low-dose mineralocorticoid (DOCA) enhances this AngII-induced intake of salt solutions (the synergy theory) in Wistar and Sprague Dawley rats but not in Fischer rats. This response is mediated via the AT-1 receptor. Electrophysiological experiments using iontophoretic application of AngII and the AT-1 receptor-specific non-peptide antagonist losartan showed excitation of neurons in the preoptic/medial septum region of urethane-anesthetized male Wistar rats. DOCA pretreatment further enhances this neuronal excitation in response to AngII and reduces the responses to losartan. This generated the hypothesis that DOCA-enhanced AngII-induced neuronal excitation is the neural support for the synergy theory. AT-2 receptors modulate these intake responses depending on sodium in the diet, and diuretic-induced dehydration during pregnancy produces a higher salt intake in the offspring. AngII-induced salt and water intakes were tested in offspring from Sprague Dawley mothers with only 1.8% NaCl to drink in which half were treated with furosemide. The important observations were a) the AT-1 antagonist alone suppressed intakes in offspring from mothers not treated with furosemide, b) both AT-1 and AT-2 antagonists suppressed intakes in offspring from furosemide-treated mothers, and c) combined administration of AT-1 and AT-2 antagonists greatly suppressed water intake in offspring from mothers not treated with furosemide. These results suggest that AT-1 and AT-2 receptors have variable properties (receptor number and/or second messengers). Furthermore, the activity and function of these central AngII receptors depend on the background mineralocorticoid levels. The exact mechanism of this influence, however, remains to be determined
Disciplinas: Medicina
Palabras clave: Endocrinología,
Neuroendocrinología,
Aldosterona,
Actividad neuronal,
Mineralocorticoides,
Iontoforesis
Keyword: Medicine,
Endocrinology,
Neuroendocrinology,
Aldosterone,
Neuronal activity,
Mineralocorticoids,
Iontophoresis
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