Distribution and Function of Neuropeptides W/B Signaling System

Abstract

Neuropeptide W (NPW) and neuropeptide B (NPB) are two structurally and functionally related regulatory peptides, which are highly expressed in several brain regions and, additionally, in some peripheral tissues. Nevertheless, their distributions in the tissues are not similar. They act on target tissues via two subtypes of G protein-coupled receptors which are designated as NPBWR1 (GPR7) and NPBWR2 (GPR8), respectively, and possess different binding affinities. NPB activates NPBWR1, whereas NPW stimulates both the receptors with similar potency. Both of these peptides takes a part in the central regulation of neuroendocrine axes, feeding behavior, energy homeostasis, cardiovascular functions, circadian rhythm, pain sensation, modulation of inflammatory pain, and emotions. Over the past few years, studies have shown that NPB is also involved in sleep regulation. On the contrary, NPW participates in regulation of vascular myogenic tone, inhibits gastric tension sensitive vagal afferents and insulin secretion. Also, expression of NPW in the stomach is regulated by feeding. Abovementioned findings clearly demonstrate the functional diversity among NPW versus NPB signaling systems. In this review, signal transduction pathways of NPW/NPB are critically evaluated and observed together with mapping of expression of their signaling systems.

Identification of NPB, NPW and Their Receptor in the Rat Heart

“…So far, we can only speculate about the function of this signaling system in the heart, because very little information is currently available in the literature. It has been demonstrated that NPB/W signaling system is involved in the regulation of blood pressure both at the central and peripheral levels [1]. Our finding demonstrating the presence of NPB within smooth muscle cells of coronary circulation supports the idea that NPB could be involved in regulation of coronary circulation.…”

“…The presence and tissue distribution of individual members of the NPB/W signaling system were studied by several working groups in the central nervous system, and detailed information is available in the literature [1]. It has been suggested that the NPB/W signaling system is involved in several central regulations including regulation of neuroendocrine functions; regulation of feeding activity; autonomic regulation; and activation of stress axis, pain sensation and energy homeostasis.…”

“…Additionally, it plays a role in emotions, anxiety and fear [12]. Despite the action throughout common receptor, NPB and NPW exert some differences in their biological activities [1].…”

“…Additionally, NPBWR1 mRNA expression is regulated by leptin, NPW and ghrelin in the neurons of nodose ganglia [23]. NPB is involved in sleep regulation [1].…”

“…Biological activities of NPB and NPW are mediated by orphan G-protein-coupled receptors, GPR7 (also called NPBWR1) in humans, rats and mice and GPR8 (NPBWR2) in humans only. NPB and NPW together with these receptors constitute NPB/W signaling system [1].…”