Opioid-modulating properties of the neuropeptide FF system

Opioid receptors are involved in the control of pain perception in the central nervous system together with endogenous neuropeptides, termed opioid-modulating peptides, participating in a homeostatic system. Neuropeptide FF (NPFF) and related peptides possess anti-opioid properties, the cellular mechanisms of which are still unclear. The purpose of this review is to detail the phenomenon of cross-talk taking place between opioid and NPFF systems at the in vivo pharmacological level and to propose cellular and molecular models of functioning. A better knowledge of the mechanisms underlying opioid-modulating properties of NPFF has potential therapeutic interest for the control of opioid functions, notably for alleviating pain and/or for the treatment of opioid abuse.