Dynorphin B is a 13-residue opioid peptide released from the cleavage of prodynorphin and found widely distributed in the central nervous system. It acts as a κ1b-opioid receptor agonist (Ki = 1.1 nM) and has been implicated in antinociceptive functions. Dynorphin B has also been used to prime cardiogenesis in pluripotent embryonic stem cells.
