Central nitrergic system regulation of neuroendocrine secretion, fluid intake and blood pressure induced by angiotensin-II

Made available in DSpace on 2019-09-12T16:56:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2010Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Background: Nitric oxide (NO) synthesis has been described in several circumventricular and hypothalamic structures in the central nervous system that are implicated in mediating central angiotensin-II (ANG-II) actions during water deprivation and hypovolemia. Neuroendocrine and cardiovascular responses, drinking behavior, and urinary excretions were examined following central angiotensinergic stimulation in awake freely-moving rats pretreated with intracerebroventricular injections of N omega-nitro-L-arginine methyl ester (L-NAME, 40 mu g), an inhibitor of NO synthase, and L-arginine (20 ug), a precursor of NO. Results: Injections of L-NAME or ANG-II produced an increase in plasma vasopressin (VP), oxytocin (OT) and atrial natriuretic peptide (ANP) levels, an increase in water and sodium intake, mean arterial blood pressure and sodium excretion, and a reduction of urinary volume. L-NAME pretreatment enhanced the ANG-II response, while L-arginine attenuated VP and OT release, thirst, appetite for sodium, antidiuresis, and natriuresis, as well as pressor responses induced by ANG-II. Discussion and conclusion: Thus, the central nitrergic system participates in the angiotensinergic responses evoked by water deprivation and hypovolemia to refrain neurohypophysial secretion, hydromineral balance, and blood pressure homeostasis.[Saad, Wilson A.; Camargo, Luiz A.; Elias, Lucila L. K.] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Physiol, Neuroendocrinol Lab, BR-14049 Ribeirao Preto, SP, Brazil[Reis, Wagner L.; Antunes-Rodrigues, Jose] Paulista State Univ Araraquara, UNESP, Sch Dent, Dept Physiol, Araraquara, SP, Brazil[Reis, Wagner L.] Universidade de Taubaté (Unitau) , Basic Inst Biosci[Reis, Wagner L.] Centro Univ Araraquara, Dept Exact & Nat Sci, Araraquara, SP, Brazi