| Journal: | Brazilian journal of medical and biological research |
| Database: | PERIÓDICA |
| System number: | 000350347 |
| ISSN: | 0100-879X |
| Authors: | Thornton, S.N1 Omouessi, S.T1 Falconetti, C1 |
| Institutions: | 1Universite Henri Poincare-Nancy I, Faculte de Medecine, Nancy, Meurthe-et-Moselle. Francia |
| Year: | 2007 |
| Season: | May |
| Volumen: | 40 |
| Number: | 5 |
| Pages: | 699-705 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental, aplicado |
| English abstract | 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 |
| Disciplines: | Medicina |
| Keyword: | Endocrinología, Neuroendocrinología, Aldosterona, Actividad neuronal, Mineralocorticoides, Iontoforesis |
| Keyword: | Medicine, Endocrinology, Neuroendocrinology, Aldosterone, Neuronal activity, Mineralocorticoids, Iontophoresis |
| Full text: | Texto completo (Ver HTML) |
