Prodynorphin (PDYN) binds to k-opioid receptors (KOPr; encoded by OPRK1) and is known to regulate dopaminergic tone, making this system important for drugs addiction.
Drug addiction is a novelty-seeking personality trait that is associated with the candidate genes OPRD1 (opioid delta receptors), OPRK1 (opioid kappa receptors) and PDYN (prodynorphin).