Abstract
Arodyn (aromatic dynorphin) is a novel analogue of the opioid peptide dynorphin A with a nonbasic N-terminus that exhibits nanomolar affinity (Ki = 10 nM) and remarkable selectivity for κ opioid receptors (Ki ratio (κ/μ/δ) = 1/174/583). Arodyn completely reverses the agonism of dynorphin A (1-13)NH2 in a concentration-dependent manner in the adenylyl cyclase assay. Thus arodyn is a novel κ opioid receptor selective antagonist that will be useful to study these receptors.