Basal and thirst-evoked vasopressin secretion in rats with electrolytic lesion of the medio-ventral septal area.

Electrolytic lesion of the medio-ventral septal (MVS) area produces, 3 days after the surgery, a remarkable increase of daily diuresis and water intake in the rat. This polyuria and polydipsia is associated with decreased levels of circulating radioimmunoassayable vasopressin. In addition, if these lesioned animals were water-deprived (48 h), the usual vasopressin release observed in sham-lesioned and normal controls was markedly blunted. These results suggest that the MVS area exerts a modulatory control on vasopressin secretion both in basal and thirst-evoked conditions.