Dynorphin 1–17, (DYN 1–17) opioid peptide produces antinociception following binding to the kappa-opioid peptide (KOP) receptor. Upon synthesis and release in inflamed tissues by immune cells, DYN 1–17 undergoes rapid biotransformation and yields a unique set of opioid and non-opioid fragments. Some of these major fragments possess a role in immunomodulation, suggesting that opioid-targeted therapeutics may be effective in diminishing the severity of inflammatory disorders.

Rahiman, S. S. F., Morgan, M., Gray, P., Shaw, P. N., & Cabot, P. J. (2016). Dynorphin 1-17 and Its N-Terminal Biotransformation Fragments Modulate Lipopolysaccharide-Stimulated Nuclear Factor-kappa B Nuclear Translocation, Interleukin-1beta and Tumor Necrosis Factor-alpha in Differentiated THP-1 Cells. PloS one, 11(4), e0153005.

Dynorphin A (1–17), an endogenous opioid neuropeptide, can have pathophysiological consequences at high concentrations through actions involving glutamate receptors. Despite evidence of excitotoxicity, the basic mechanisms underlying dynorphin-induced cell death have not been explored. To address this question, we examined the role of caspase-dependent apoptotic events in mediating dynorphin A (1–17) toxicity in embryonic mouse striatal neuron cultures. In addition, the role of opioid and/or glutamate receptors were assessed pharmacologically using MK(+)801, a non-equilibrium N-methyl-D-aspartate (NMDA) antagonist; CNQX, a competitive α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)/kainate antagonist; or (−)-naloxone, a general opioid antagonist.

Singh, I. N., Goody, R. J., Goebel, S. M., Martin, K. M., Knapp, P. E., Marinova, Z., ... & Hauser, K. F. (2003). Dynorphin A (1–17) induces apoptosis in striatal neurons in vitro through α-amino-3-hydroxy-5-methylisoxazole-4-propionate/kainate receptor-mediated cytochrome C release and caspase-3 activation. Neuroscience, 122(4), 1013-1023.

Opioids inhibit release of primary afferent transmitters but it is unclear whether the converse occurs. To test the hypothesis that primary afferent transmitters influence opioid-ergic tone, we studied the functional and anatomical relationships between pituitary adenylyl cyclase-activating polypeptide (PACAP) and dynorphin 1-17 (Dyn) in spinal cord. We found that activation of the PACAP-specific receptor PAC1 (PAC1R) inhibited, whereas PAC1R blockade augmented, spinal release of Dyn. It is noteworthy that in the formalin-induced pain model PAC1R blockade (via PACAP6-38) also resulted in antinociception that was abolished by spinal κ-opioid receptor blockade.

Liu, N. J., Schnell, S. A., Schulz, S., Wessendorf, M. W., & Gintzler, A. R. (2011). Regulation of spinal dynorphin 1-17 release by endogenous pituitary adenylyl cyclase-activating polypeptide in the male rat: relevance of excitation via disinhibition. Journal of Pharmacology and Experimental Therapeutics, 336(2), 328-335.