Dynorphin A

Dynorphin A is an endogenous opioid peptide of 17 amino acids that preferentially binds to and activates kappa-opioid receptors, though it also has affinity for mu and delta receptors at higher concentrations. It is derived from the precursor protein prodynorphin and plays a complex role in pain modulation, stress responses, and dysphoria.

Unlike mu-opioid agonists, kappa receptor activation can produce analgesia without typical euphoria but may induce aversive psychological effects. Dynorphin also has non-opioid actions at high concentrations, including NMDA receptor modulation..

Dynorphin A is in the research phase with limited clinical data in humans. Current evidence is primarily derived from preclinical (animal or in vitro) studies.