Distribution of neuropeptide W in the rat brain

Abstract 

Neuropeptide W (NPW), which was recently isolated from the porcine hypothalamus, has been identified as the endogenous ligand of the orphan G protein-coupled receptors GPR7 (NPBWR1) and GPR8 (NPBWR2). Infusion of NPW increases food intake in the light phase, whereas in the dark phase, it has the opposite effect. In this study, we used RT-PCR analysis to examine the gene expression of NPW mRNA in the rat brain, and performed a detailed analysis of the distribution of NPW-positive neurons by use of immunohistochemistry at both the light and electron microscopic levels. NPW mRNA expression was demonstrated in the hypothalamic paraventricular nucleus (PVN), arcuate nucleus (ARC), ventromedial nucleus (VMH) and lateral hypothalamus (LH). At the light microscopic level, NPW-like immunoreactive (NPW-LI) cell bodies were found in the preoptic area (POA), PVN, ARC, VMH, LH, PMD (dorsal premammillary nucleus), periaqueductal gray (PAG), lateral parabrachial nucleus (LPB), and prepositus nucleus (Pr). NPW-LI axon terminals were shown in the POA, bed nucleus of the stria terminalis (BST), amygdala, PVN, ARC, VMH, LH, and PAG, LPB. In addition, at the electron microscopic level, NPW-LI cell bodies and dendritic processes were often seen to receive inputs from other unknown neurons in the ARC, PVN, VMH and amygdala. Our observations indicate that NPW-LI neurons widely distributed in the rat brain region. These finding suggest that NPW may have important roles in feeding behavior, energy homeostasis, emotional response and regulation of saliva secretion.

Abbreviations: ac, Aterior commissure, aca, Aterior commissure, anterior part, acp, Aterior commissure, posterior part acp, AP, Area postrema, Aq, Aqueduct, Arc, Arcuate hypothalamic nucleus, ArcL, Arcuate nucleus, lateral part ArcL, BSTLP, Bed nucleus of the stria terminalis, lateral division, posterior part, BSTMA, Bed nucleus of the stria terminalis, medial division, anterior part, BSTMV, Bed nucleus of the stria terminalis, medial division, ventral part, BSTMPL, Bed nucleus of the stria terminalis, medial division, posterolateral part, Ce, Central amygdaloid nucleus, CeC, Central amygdaloid nucleus, capsular part, CeL, Central amygdaloid nucleus, lateral division, CeM, Central amygdaloid nucleus, medial division, cp, Cerebral peduncle, basal part, DLPAG, Ddorsolateral periaqueductal gray, DTM, Dorsal tuberomammillary nucleus, DRC, Dorsal raphe nucleus, caudal part, ec, External capsule, EW, Edinger–Westphal nucleus, f, Fornix, HDB, Nucleus of the horizontal limb of the diagonal band, ic, Internal capsule, ICj, Islands of Calleja, IPR, Interpeduncular nucleus, rostral subnucleus, LA, Lateroanterior hypothalamic nucleus, LGP, Lateral globus pallidus, LH, Lateral hypothalamic area, LPAG, Ventrolateral periaqueductal gray, LSV, Lateral septal nucleus, ventral part, Ml, Medial lemniscus, LDTg, Laterodorsal tegmental nucleus, MnR, Median raphe nucleus, MPA, Medial preoptic area, MPO, Medial preoptic nucleus, MPOC, Medial preoptic nucleus, central part, MRe, Mammillary recess of the 3rd ventricle, ox, Optic chiasm, opt, Optic tract, OPT, Olivary pretectal nucleus, PaAP, Paraventricular hypothalamic nucleus, anterior parvicellular part, PaMP, Paraventricular hypothalamic nucleus, medial parvicellular part, PaPo, Paraventricular hypothalamic nucleus, posterior part, PaV, Paraventricular hypothalamic nucleus, ventral part, Pe, Periventricular hypothalamic nucleus, PMD, Premammillary nucleus, dorsal part, RMg, Raphe magnus nucleus, Py, Pyramidal tract, pr, Prepositus nucleus, scp, Superior cerebellar peduncle, Sch, Suprachiasmatic nucleus, SO, Supraoptic nucleus, sox, Supraoptic decussation, st, Stria terminalis, VLPAG, Ventrolateral periaqueductal gray, VMPO, Ventromedial preoptic nucleus, VMHA, Ventromedial hypothalamic nucleus, anterior part, VTA, Ventral tegmental area, VP, Ventral pallidum, 7, Accessory abducens/facial nucleus, 12, Hypoglossal nucleus

Keywords: Neuropeptide W, Hypothalamus, Distribution, Immunohistochemistry, Rat