Dynorphin B-29: chemical synthesis and pharmacological properties in opioid systems in vitro

Porcine dynorphin B-29 was synthesized by solid phase procedures and purified using gel filtration, ion exchange, reverse phase liquid chromatography and preparative high pressure liquid chromatography (HPLC). Binding experiments using brain tissue indicated this peptide displaced mu and k ligands equally well and had significant, though less, affinity for delta. In isolated tissue systems, its potency ranked as follows: guinea pig ileum, mouse vas, rabbit vas, and rat vas. Interestingly, all IC50s were reduced in the presence of peptidase inhibitors, particularly in the rabbit vas. These results indicate that dynorphin B-29 like dynorphin, interacts with multiple receptors in the brain, as well as in isolated tissue systems.