Selective NOP receptor antagonist (Ki values are 0.33, 57.6, 160.5 and 2109 nM for NOP, μ-, κ- and δ-receptors respectively). Antagonizes the pronociceptive action of nociceptin (Cat. No. 0910) in an acute pain model. Potentiates the action of morphine in morphine-tolerant animals and blocks hyperalgesia in an inflammatory pain model.