Neuropeptide FF Modulates Neuroendocrine and Energy Homeostasis through Hypothalamic Signaling

Neuropeptide FF (NPFF) is known as a morphine-modulating peptide and was first isolated in 1985. It has been characterized as an RF-amide peptide. The traditional role of NPFF is mediation of the pain response, and it displays both anti-opioid and pro-opioid actions through central nervous system. In the recent decade, additional evidence has revealed some untraditional features of NPFF, such as regulation of the neuroendocrine system, energy homeostasis, anti-inflammation, pain transmission, and peripheral modulation of adipose tissue macrophages. Neuropeptide FF receptor 2 (NPFFR2) is a physiological receptor of NPFF, and the actions of NPFF may occur through downstream NPFFR2 signaling. NPFF and NPFFR2 increase the neuronal activity in various areas of the hypothalamus to modulate the hypothalamicupituitaryuadrenal axis, the autonomic nervous system, food intake, and energy balance. These underlying cellular mechanisms have been explored in the past few years. Here, we review the impact of NPFF and related RF-amide peptides on hypothalamic function. The interaction of NPFF with NPFFR2 in the hypothalamus is emphasized, and NPFF-NPFFR2 system may represent an important therapeutic target in hypothalamic-related disorders in the future.