TASP0390325 blocks the anterior pituitary V1B receptor in vivo. Oral administration of TASP0390325 antagonized the increase in plasma ACTH levels induced by CRF/dDAVP in rats, indicating that TASP0390325 blocks the anterior pituitary V1B receptor in vivo. TASP0390325 (1 mg/kg) significantly antagonizes CRF/dDAVP-induced plasma ACTH in rats. Oral administration of TASP0390325 also exerts antidepressant effects in two models of depression (a forced swimming test and an olfactory bulbectomy model).