Our data demonstrate that the blockade of μ−opioid receptors potentiated the anxiolytic-like effect of oxytocin, whereas the blockade of κ−opioid receptors inhibited the anxiolytic-like effect of oxytocin, suggesting that the μ− and κ−opioid receptor systems differentially modulate the function of oxytocin with respect to anxiety-like behavior. Here, OXT is linked to Anxiety.