Resumen de Influence of nitric oxide synthase inhibition on vasopressin and corticosterone secretion during water deprivation in rats
Bessem Mornagui, Raja Rezg, Abir Grissa, Monique Duvareille, Claude Gharib, Abdelaziz Kamoun, Saloua El-Fazaa, Najoua Gharbi
Nitric oxide (NO) is a short-lived radical that functions as a neurotransmitter in the central nervous system and plays a physiological role in the regulation of hypothalamic�pituitary�adrenal axis and vasopressinergic axis. In the present study, we aimed to investigate the interaction between the generation of NO and vasopressin (AVP) and corticosterone release after 3 days of water deprivation in rats. Animals were previously treated with intraperitoneal (i.p.) saline or l-nitro-arginine methyl ester (L-NAME) injection. l-NAME is a nonspecific inhibitor of nitric oxide synthases. In control rats given i.p. saline or l-NAME, hypothalamic, pituitary, and plasma AVP levels and plasma corticosterone did not change from baseline levels (p > 0.05). Three days of water deprivation increased significantly the corticosterone levels in plasma (p < 0.01) and AVP levels in hypothalamus and plasma (p < 0.01), but not in pituitary, which showed a significant decrease. These variations were concomitant with the elevation of nitrates/nitrates in plasma. l-NAME injection abolished significantly (p < 0.01) the elevation of plasma corticosterone and hypothalamic AVP levels induced by water deprivation. These findings showed that in water-deprived rats, nitric oxide synthase inhibition by l-NAME inhibits corticosterone and vasopressin release, suggesting a potent stimulatory role of NO.
