Hypertonic saline mimics the effects of vasopressin and social recognition in rats

Injection of hypertonic saline to adult male rats following exposure to a juvenile, at a dose known to release peripheral and central vasopressin (10ml/kg i.p. of an 0.5M solution), decreased social exploration of the same juvenile when it was presented 2h later. This effect of hypertonic saline was blocked by pretreatment with subcutaneous injection of 30mg/kg dPTyr (Me) AVP, an antagonist of the vasopressor receptors of vasopressin, in intact but not in castrated male rats. These results are interpreted in terms of the involvement of androgen-dependent vasopressinergic neurotransmission in social recognition.