抄録
It is known that water deprivation or injection of hypertonic saline induces anorexia. The present study examined the possible involvement of vasopressin in the suppression of food intake during high plasma osmolality. Intraperitoneal injection of vasopressin (20 μg/kg) into male rats significantly suppressed food intake for 1 hr. This anorectic effect of vasopressin was reversed by simultaneous injection of a peptide antagonist for V1 receptor (40 μg/kg), but not for V2 receptor (40 μg/kg). Intraperitoneal injection of hypertonic saline (20% NaCl, 2 ml/kg) similarly suppressed food intake for 2 hr, which was associated with a transient increase in plasma vasopressin concentrations. This hypertonic saline-induced suppression of food intake was blocked by a V1 receptor antagonist. Vasopressin (40 ng/2 μl) directly administered into the third ventricle of the brain also suppressed food intake for 1 hr. These results suggest that vasopressin participates in the suppression of food intake during high plasma osmolality, the action of which is mediated by V1 receptors in the brain.
