Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Following the cloning of the opioid receptors mu, kappa, and delta, we conducted a search for related receptors. Using oligonucleotides based on the opioid and also the structurally related somatostatin receptors, we amplified genomic DNA using the polymerase chain reaction and isolated fragments of novel G protein-coupled receptor genes. Two of these gene fragments designated clones 12 and 11 were used to isolate the full-length genes. The intronless coding sequences of these genes, named GPR7 and GPR8, shared 70% identity with each other, and each shared significant similarity with the sequences encoding transmembrane regions of the opioid and somatostatin receptors. GPR7 was mapped to chromosome 10q11.2-q21.1 and GPR8 to chromosome 20q13.3. Northern blot analysis using human mRNA demonstrated expression of GPR7 mainly in cerebellum and frontal cortex, while GPR8 was located mainly in the frontal cortex. In situ hybridization revealed expression of GPR7 in the human pituitary. A partial sequence of the mouse orthologue of GPR7 was obtained, and in situ hybridization demonstrated expression in discrete nuclei of brain, namely suprachiasmatic, arcuate, and ventromedial nuclei of hypothalamus. A stable cell line expressing the GPR7 gene was created, but expression levels of the receptor were low. The available pharmacology indicated binding to several opioid drugs such as bremazocine, levorphanol, and beta-FNA, but not to the opioid receptor subtype-selective mu, delta, or kappa agonists.
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PMID:The cloning and chromosomal mapping of two novel human opioid-somatostatin-like receptor genes, GPR7 and GPR8, expressed in discrete areas of the brain. 759 Jul 51

GPR7 and GPR8, orphan G protein-coupled receptor (GPCR) genes, expressed in the brain and periphery share highest sequence identity to each other and significant similarity with opioid and somatostatin receptors. To further our knowledge of GPR7's physiological function, we performed in situ hybridization analyses of rat brain to reveal specific patterns of expression in the brain. GPR7 mRNA was found to be discretely localized in areas of the amygdala, hippocampus, hypothalamus and cortex. We previously reported that GPR7 was highly conserved in both human and rodent orthologs while GPR8 was not found in the rodent [9]. We speculated that GPR8 originated after the divergence of the human and rodent. Using primers designed from human GPR8, we isolated lemur GPR8 and subsequently aligned human, monkey, and lemur GPR8 orthologs to design primers recognizing highly conserved regions of GPR8. Using these primers, orthologs of GPR7 and GPR8 were isolated by the PCR from rabbit, tree shrew, and flying lemur, as well as GPR7 in the rat. Subsequent analysis of the clones obtained demonstrated that both GPR7 and GPR8 sequences were highly conserved amongst the species studied, but a rodent GPR8 was not isolated. The absence of a GPR8 gene in the rodent suggests that GPR8 originated from gene duplication of GPR7 after the rodent line diverged from the rabbit, tree shrew, flying lemur, lemur, monkey and human lines. In addition, the taxonomic distribution of GPR8 is consistent with molecular studies grouping rabbits with primates, tree shrews and flying lemurs rather than with rodents.
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PMID:Two related G protein-coupled receptors: the distribution of GPR7 in rat brain and the absence of GPR8 in rodents. 1040 91

GPR7 and GPR8 are two structurally related orphan G protein-coupled receptors, presenting high similarities with opioid and somatostatin receptors. Two peptides, L8 and L8C, derived from a larger precursor, were recently described as natural ligands for GPR8 (Mori, M., Shimomura, Y., Harada, M., Kurihara, M., Kitada, C., Asami, T., Matsumoto, Y., Adachi, Y., Watanabe, T., Sugo, T., and Abe, M. (December, 27, 2001) World Patent Cooperation Treaty, Patent Application WO 01/98494A1). L8 is a 23-amino acid peptide, whereas L8C is the same peptide with a C terminus extension of 7 amino acids, running through a dibasic motif of proteolytic processing. Using as a query the amino acid sequence of the L8 peptide, we have identified in DNA databases a human gene predicted to encode related peptides and its mouse ortholog. By analogy with L8 and L8C, two peptides, named L7 and L7C could result from the processing of a 125-amino acid human precursor through the alternative usage of a dibasic amino acid motif. The activity of these four peptides was investigated on GPR7 and GPR8. In binding assays, L7, L7C, L8, and L8C were found to bind with low nanomolar affinities to the GPR7 and GPR8 receptors expressed in Chinese hamster ovary (CHO)-K1 cells. They inhibited forskolin-stimulated cAMP accumulation through a pertussis toxin-sensitive mechanism. The tissue distribution of prepro-L7 (ppL7) and prepro-L8 (ppL8) was investigated by reverse transcription-PCR. Abundant ppL7 transcripts were found throughout the brain as well as in spinal cord, spleen, testis, and placenta; ppL8 transcripts displayed a more restricted distribution in brain, with high levels in substantia nigra, but were more abundant in peripheral tissues. The ppL7 and ppL8 genes therefore encode the precursors of a class of peptide ligands, active on two receptor subtypes, GPR7 and GPR8. The distinct tissue distribution of the receptor and peptide precursors suggest that each ligand and receptor has partially overlapping but also specific roles in this signaling system.
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PMID:Identification of natural ligands for the orphan G protein-coupled receptors GPR7 and GPR8. 1240 9

Neuropeptide W-23 (NPW23) is an endogenous ligand of both GPR7 and GPR8, and neuropeptide B (NPB) is an endogenous ligand of GPR7. GPR7 mRNA has been detected in regions of the cortex, the hippocampus, the hypothalamus, and the spinal cord in the rat, but GPR8 has not been found in rodents. GPR7 and GPR8 receptors have structural features in common with both opioid and somatostatin receptors. The effects of intrathecal (i.t.) application of NPW23 and NPB were tested in two inflammatory pain models (plantar injection of formalin or carrageenan) and two thermal nociceptive tests (52.5 degrees C and 50.5 degrees C hot plates) and one mechanical nociceptive test in the rat. I.t. injection of either NPW23 or NPB decreased the number of agitation behaviors induced by paw formalin injection and attenuated the level of mechanical allodynia, but not the level of thermal hyperalgesia, induced by paw carrageenan injection in a dose-dependent manner at a dose between 0.1 and 10 microg, significantly. The effects of either 10 microg of NPW23 or 10 microg of NPB were not antagonized by 10 microg of naloxone. I.t. injection of either NPW23 or NPB had no effect in both the 52.5 degrees C hot plate test or in the 50.5 degrees C hot plate tests at a dose between 1 and 100 microg. I.t. injection of either 10 microg of NPW23 or 10 microg of NPB had no effect in the mechanical nociceptive test. I.t. injection of either 10 microg of NPW23 or 10 microg of NPB significantly suppressed the expression of Fos-like immunoreactivity of the L4-5 spinal dorsal horn induced by paw formalin injection. These data suggest that both spinally-applied NPW23 and NPB suppressed the input of nociceptive information to the spinal dorsal horn, produced an analgesic effect in the formalin test, and attenuated the level of mechanical allodynia in the carrageenan test, and that either spinally applied NPW23 or spinally applied NPB had no effect in the physiological condition.
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PMID:Anti-hyperalgesic effects of intrathecally administered neuropeptide W-23, and neuropeptide B, in tests of inflammatory pain in rats. 1591 Jul 67

Neuropeptide W (NPW) is a regulatory peptide that acts via two subtypes of G protein-coupled receptors, GPR7 and GPR8. Evidence has been provided that NPW is involved in the central regulation of energy homeostasis and feeding behavior. In this study, we examined the effects of NPW on insulin release and localization of NPW in the rat pancreas. NPW (10-100 nM) significantly increased insulin release in the presence of 8.3 mM, but not 2.8 mM, glucose in the isolated rat islets. By fura-2 microfluorometry, NPW (1-100 nM) concentration-dependently increased cytosolic Ca(2+) concentration ([Ca(2+)](i)) at 8.3 mM glucose in rat single beta-cells. The NPW-induced [Ca(2+)](i) increase was abolished under external Ca(2+)-free conditions and by an L-type Ca(2+) channel blocker nifedipine (10 microM). RT-PCR analysis revealed that mRNA for NPW was expressed in the rat pancreas and hypothalamus. Double immunohistochemical analysis showed that NPW-immunoreactivity was found in islets and co-localized with insulin-containing beta-cells, but not glucagon-containing alpha-cells and somatostatin-containing delta-cells. These results suggest that NPW could serve as a local modulator of glucose-induced insulin release in rat islets. NPW directly activates beta-cells to enhance Ca(2+) influx through voltage-dependent L-type Ca(2+) channels and potentiates glucose-induced insulin release.
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PMID:Neuropeptide W in the rat pancreas: potentiation of glucose-induced insulin release and Ca2+ influx through L-type Ca2+ channels in beta-cells and localization in islets. 1786 32