Neuropeptide B and W: neurotransmitters in an emerging G‐protein‐coupled receptor system

Singh, Gurminder; Davenport, Anthony P.

doi:10.1038/sj.bjp.0706825

Cited by 48 publications

(37 citation statements)

References 45 publications

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“…The dog has three chromosomes and the opossum has two chromosomes that correspond to chicken chromosome 3 indicating that the translocations in mammals occurred in two steps. It has been suggested that the NPBW receptors are closely related to both the opioid and the somatostatin receptors (44,45). The phylogenetic tree (Fig.…”

Section: Discussionmentioning

confidence: 99%

Evolution of vertebrate opioid receptors

Dreborg

Sundström

Larsson

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

110

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The opioid peptides and receptors have prominent roles in pain transmission and reward mechanisms in mammals. The evolution of the opioid receptors has so far been little studied, with only a few reports on species other than tetrapods. We have investigated species representing a broader range of vertebrates and found that the four opioid receptor types (delta, kappa, mu, and NOP) are present in most of the species. The gene relationships were deduced by using both phylogenetic analyses and chromosomal location relative to 20 neighboring gene families in databases of assembled genomes. The combined results show that the vertebrate opioid receptor gene family arose by quadruplication of a large chromosomal block containing at least 14 other gene families. The quadruplication seems to coincide with, and, therefore, probably resulted from, the two proposed genome duplications in early vertebrate evolution. We conclude that the quartet of opioid receptors was already present at the origin of jawed vertebrates Ϸ450 million years ago. A few additional opioid receptor gene duplications have occurred in bony fishes. Interestingly, the ancestral receptor gene duplications coincide with the origin of the four opioid peptide precursor genes. Thus, the complete vertebrate opioid system was already established in the first jawed vertebrates.chromosome ͉ G protein-coupled receptor ͉ gene duplication S everal opioid peptides, including endorphin and enkephalins, are important regulators of nociceptive neurotransmission and reward mechanisms in mammals. Specific binding sites in the brain for opioid compounds were first reported in 1973 (1-3), and it was soon evident that more than one type of binding site existed (4). Subsequently three distinct opioid receptors were identified and designated delta, kappa, and mu. These receptors were cloned and found to be encoded by separate genes belonging to the superfamily of rhodopsin-like G protein-coupled receptors (GPCRs) (5-8). The genes for the opioid receptors (OPR) have been named OPRD1 (delta), OPRK1 (kappa), and OPRM1 (mu) by the HUGO Gene Nomenclature Committee (HGNC).Homology searches resulted in the discovery of a fourth receptor in both rodents and humans initially named ORL1 for opioid receptor-like (9) or LC132 (10). This receptor shows 48-49% identity to the other three human receptors, which display 55-58% identity among one another. The receptor has been named NOP by the International Union of Basic and Clinical Pharmacology and its gene has been named OPRL1 by HGNC. An endogenous peptide ligand with some similarity to the other opioid peptides was discovered and named nociceptin (11) or orphanin FQ (12).The evolution of the endogenous opioid peptide ligands has been studied extensively and the major peptide ligands are generated from four prepropeptides that are encoded by separate genes in tetrapods. The genes arose by duplications in the common ancestor of tetrapods and bony fishes (13). Opioid receptor sequences have been reported for a few nonmammalian tetrapods (1...

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Section: Discussionmentioning

confidence: 99%

Evolution of vertebrate opioid receptors

Dreborg

Sundström

Larsson

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

110

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“…In rodents where NPBWR2 is absent, its counterpart is described as being similar to neuropeptide B/W receptor 2 (formerly GPR8-like) (1)(2)(3).…”

Section: Introductionmentioning

confidence: 99%

Neuropeptide W exerts a potent suppressive effect on blood leptin and insulin concentrations in the rat

Ruciński

Nowak²,

Chmielewska³

et al. 2007

Int J Mol Med

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Abstract. Neuropeptide B/W receptor 1 (NPBWR1) and neuropeptide B/W receptor 2 (NPBWR2) are two structurally related orphan receptors linked to protein G. In rodents NPBWR2 is absent, and its counterpart is described as being similar to neuropeptide B/W receptor 2. Endogenous ligands of these receptors have been identified. One of them is 29 amino acid residues long, uniquely modified with bromine and, thus, termed neuropeptide B (NPB). The other, neuropeptide W (NPW), has been identified in two molecular forms of 23 and 30 amino acids (NPW23 and NPW30), respectively. Both NPB and NPW affect food intake and energy expenditure. Since leptin, a potent anti-obesity hormone, and insulin are involved in the control of energy homeostasis, the present study aimed to investigate whether NPB and NPW affect leptin and insulin secretion in the rat. RT-PCR technique revealed the presence of ppNPB, ppNPW, NPBWR1 and NPBWR2-like mRNAs in isolated pancreatic islets of the rat. NPB and NPW immunoreactivities were observed in all of the cells of the pancreatic islets. Only when a higher dose was administered (3 nmol/100 g body weight) did NPW transiently lower blood insulin levels whereas NPB injection did not alter insulinaemia in the studied rats. At 30 min, but not 60, of the experiment, NPW notably lowered blood leptin concentrations at both tested doses. On the contrary, NPB injections had no effect on blood leptin and insulin concentrations. Thus, the results suggest that NPW but not NPB exerts a potent suppressive effect on blood leptin concentrations in the rat, and this mechanism may be involved in NPW regulation of energy homeostasis.

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“…However, since no biochemical and pharmacological data are available at present, this hypothesis remains to be proved in future studies. Since an autoradiographic study has shown that high levels of 125 I-labeled NPB or NPW bindings are detected in the SCN (11,29), functional receptors may be expressed in the SCN. However, there are many evidences that they are functionally inactive.…”

Section: Anticipation Of Feeding In Restricted Feeding Schedule In Gpr7mentioning

confidence: 99%

“…Recently, its two endogenous ligands, neuropeptide B (NPB) and neuropeptide W (NPW), were identified (3,6,28,30). Although roles of this receptor on feeding, prolactin-release and pain were reported (29), the roles of GPR7 on biological rhythms have not been clarified. In the present study, we demonstrated the circadian change of GPR7 expression in the SCN, and further examined the circadian characteristics of mice deleted with GPR7 gene (10).…”

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confidence: 99%

Circadian characteristics of mice depleted with GPR7

et al. 2009

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GPR7, now known as a receptor of neuropeptide B and neuropeptide W, is expressed in neurons of the suprachiasmatic nucleus (SCN), the mammalian circadian center. By the quantitative in situ hybridization, we demonstrated that GPR7 mRNA showed a significant circadian rhythm in the SCN showing a peak at early subjective night in both light-dark and constant dark. We characterized the circadian feature of GPR7-knockout mice, but the period length and the phase-dependent phase shift to light exposure were not disordered in GPR7-knockout mice. Moreover, the food-anticipatory behavior in restricted feeding schedule was observed in this gene-deleted mouse similar to wild-type. These results indicate that the role of GPR7 may be subtle or limited in relation to the circadian clock despite its robust expression in the SCN.Most organisms display a physiological and behavioral rhythm with periods of nearly 24 hours. In mammals, the central circadian oscillator is located in the hypothalamic suprachiasmatic nucleus (SCN) (12). Here the circadian rhythm is generated in the oscillator cells by a transcription/translation based autoregulatory negative feedback loop in which the protein products of a set of clock genes inhibit their own transcription (23,26). In SCN, this cellular rhythm is synchronized through the interaction of oscillating cells (32), and entrained to the environmental light-dark cycle by the photic and non-photic signals (9, 12). Many receptors and their intracellular signal transductions may be enrolled in this intercellular communication, and a G-protein-coupled receptor GPR7 might be this candidate, since GPR7 is highly expressed in the SCN (13). GPR7 is originally described by O'Dowd et al. (1995) (21) as a receptor having close structural resemblance to both the somatostatin-3 (SST3) receptor, and the μ-, δ-, and κ-opioid receptors. Recently, its two endogenous ligands, neuropeptide B (NPB) and neuropeptide W (NPW), were identified (3,6,28,30). Although roles of this receptor on feeding, prolactin-release and pain were reported (29), the roles of GPR7 on biological rhythms have not been clarified. In the present study, we demonstrated the circadian change of GPR7 expression in the SCN, and further examined the circadian characteristics of mice deleted with GPR7 gene (10). MATERIALS AND METHODSAnimals and behavioral rhythm monitoring. For examining the expression of GPR7, we purchased male C57B16 mice at 6 weeks age (JAPS, Osaka, Japan). Mice were housed in 12 h light/dark (LD) cycles (fluorescent light, 300 lux) at least for 2 weeks at 22 ± 2°C with freely provided diet and water. Six mice were examined for assessing the brain expression of GPR7 at ZT 16 (ZT stands for Zeitgeber time in a LD cycle; ZT0 is light-on and ZT12 is lights-off). For quantitative analysis of GPR7 in the

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Neuropeptide B and W: neurotransmitters in an emerging G‐protein‐coupled receptor system

Cited by 48 publications

References 45 publications

Evolution of vertebrate opioid receptors

Evolution of vertebrate opioid receptors

Neuropeptide W exerts a potent suppressive effect on blood leptin and insulin concentrations in the rat

Circadian characteristics of mice depleted with GPR7

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