The dynorphin/kappa-opioid system of the brain as a promising target for therapy for dependence on psychoactive substances

Dynorphin is an endogenous opioid peptide that has the largest affinity to kappa-opioid receptors (KORs). Administration of dynorphin and KOR agonists has aversive, prodysphoric, and depressogenic effects on humans and animals. We believe that the dynorphin/kappa-opioid system may play the role of negative feedback that regulates the activity of monoaminergic neurotransmission in the brain; thus, KORs may be considered as a promising target for the development of drugs for the prevention of a relapse of PAS dependence.