The first report of an antidepressant-like effect of OXT came from Arletti and Bertolini [22] who demonstrated that intra-peritoneal (i.p.)administration both, acutely, and after ten daily-repeated injections decreased immobility time in the forced swim test (FST) in mice: the most widely utilised animal model of depression [4]. This evidence concerns the gene OXT and major depressive disorder.