Nalfurafine

Nalfurafine is a ?-opioid receptor (KOR) agonist (EC50 = 0.05 nM for human receptors expressed in CHO cell membranes).{49051} It is selective for ?-opioid over ?- and ?-opioid receptors (EC50s = 0.72 and 74.1 nM, respectively). Nalfurafine (?30 ?g/kg) reduces scratching behavior induced by chloroquine (CQ; Item No. 14194) in mice, as well as locomotor activity when administered at a dose of 100 ?g/kg.{49053} In rats, nalfurafine (?0.01 mg/kg) reduces intracranial self-stimulation, lactic acid-induced stretching behavior, and scratching behavior induced by intradermal administration of serotonin (5-HT; Item No. 14332).{49054} Nalfurafine is also an orexin 1 receptor (OX1R) antagonist (Ki = 250 nM).{49052} Nalfurafine is regulated as a Schedule II compound in the United States.