Highly potent and selective NOP receptor agonist (EC50 = 1 nM). Displays > 875-fold selectivity over opioid receptors (IC50 values are 0.32, 280, > 10000 and 1500 for NOP, μ, δ and κ receptors respectively). Longer lasting and 30-fold more potent than nociceptin in vivo; pronociceptive and inhibits locomotor activity. MW (observed): 1909.18.