Role of nitric oxide in lipopolysaccharide-induced release of vasopressin in rats.

This study evaluated the role of nitric oxide (NO) in vasopressin (AVP) release induced by intravenous lipopolysaccharide (LPS) in rats previously treated with intracerebroventricular (i.c.v.) saline, L-NAME, L-arginine or sodium nitroprusside (SNP). In control rats given i.c.v. saline, L-NAME, L-arginine or SNP, AVP levels did not change from baseline. After LPS, plasma AVP increased, reaching a peak at 60 min, and returning to basal levels 4 h later in all i.c.v. pre-treated groups (P<0.05). The LPS administration in rats previously treated with L-NAME induced higher AVP levels (P<0.05) that remained elevated throughout the period of the experiment (P<0.05). These findings confirm the inhibitory role of NO in AVP secretion induced by LPS.