Adrenorphin is an endogenous opioid peptide produced from cleavage of proenkephalin A. Adrenorphin acts as an agonist at κ-opioid receptors (κORs) and μ-opioid receptors (μORs). Like other opioids, adrenorphin exhibits analgesic, antinociceptive, and gastrointestinal motility modulating activities. Adrenorphin also causes respiratory depression in animal models. In pheochromocytoma cells, adrenorphin inhibits catecholamine secretion. In animal models, it also inhibits urinary bladder muscle contractions.