Role for lateral tegmental noradrenergic neurons in the vasopressin response to hypertonic saline.

Lesions to the dorsal and ventral noradrenergic pathways were achieved by injecting 6-hydroxydopamine in the periaqueductal midbrain or lateral pons, respectively. Four to 6 weeks after surgery the rats were anaesthetized with pentobarbitone, and hypertonic saline was administered into the peritoneum. Rats with lesions of the ventral noradrenergic pathways showed a significant reduction in the saline-induced rise in plasma vasopressin concentrations, while lesions to the dorsal pathway or control injections were without effect.