| 词条 | Melatonin receptor |
| 释义 |
| Name = melatonin receptor 1A | caption = | image = | width = | HGNCid = 7463 | Symbol = MTNR1A | AltSymbols = | EntrezGene = 4543 | OMIM = 600665 | RefSeq = NM_005958 | UniProt = P48039 | PDB = | ECnumber = | Chromosome = 4 | Arm = q | Band = 35.1 | LocusSupplementaryData = }}{{infobox protein | Name = melatonin receptor 1B | caption = | image = | width = | HGNCid = 7464 | Symbol = MTNR1B | AltSymbols = | EntrezGene = 4544 | OMIM = 600804 | RefSeq = NM_005959 | UniProt = P49286 | PDB = | ECnumber = | Chromosome = 11 | Arm = q | Band = 21 | LocusSupplementaryData = -q22 }} A melatonin receptor is a G protein-coupled receptor (GPCR) which binds melatonin.[1] Three types of melatonin receptors have been cloned. The MT1 (or Mel1A or MTNR1A) and MT2 (or Mel1B or MTNR1B) receptor subtypes are present in humans and other mammals,[2] while an additional melatonin receptor subtype MT3 (or Mel1C or MTNR1C) has been identified in amphibia and birds.[3] Expression patternsIn mammals, melatonin receptors are found in the brain and some peripheral organs. However, there is considerable variation in the density and location of MT receptor expression between species.[4] MT1In humans, The MT1 subtype is expressed in the pars tuberalis of the pituitary gland, the retina and the suprachiasmatic nuclei of the hypothalamus. MT2The MT2 subtype is expressed in the retina. MT2 receptor mRNA has not been detected by in situ hybridization in the rat suprachiasmatic nucleus or pars tuberalis.[5] MT3The MT3 subtype of many non-mammalian vertebrates is expressed in various brain areas.[3] MT Receptor functionMT1In humans, The MT1 subtype's expression in the pars tuberalis of the pituitary gland and suprachiasmatic nuclei of the hypothalamus is indicative of melatonin's circadian and reproductive functional involvement. MT2In humans, the MT2 subtype's expression in the retina is suggestive of melatonin's effect on the mammalian retina occurring through this receptor. Research suggests that melatonin acts to inhibit the Ca2+-dependent release of dopamine.[5] Melatonin's action in the retina is believed to affect several light-dependent functions, including phagocytosis and photopigment disc shedding.[6] In addition to retina this receptor is expressed on the osteoblasts and is increased upon their differentiation. MT2 regulates proliferation and differentiation of osteoblasts and regulates their function in depositing bone. [7] MT2 signaling seems also involved in the pathogenesis of type 2 diabetes. MT3 binding sites are widely distributed in the brain, liver, heart, kidneys, and lungs.Recent findings from animal studies suggest possible roles in the regulation of intraocular pressure and in inflammatory responses in the microvasculature.(Abdulhadi.m) Selective LigandsAgonists
Antagonists
See also
References1. ^{{cite journal | author = Reppert SM | title = Melatonin receptors: molecular biology of a new family of G protein-coupled receptors | journal = J. Biol. Rhythms | volume = 12 | issue = 6 | pages = 528–31 | year = 1997 | pmid = 9406026 | doi = 10.1177/074873049701200606 }} 2. ^{{cite journal |vauthors=Reppert SM, Weaver DR, Godson C | title = Melatonin receptors step into the light: cloning and classification of subtypes | journal = Trends Pharmacol. Sci. | volume = 17 | issue = 3 | pages = 100–02 | year = 1996 | pmid = 8936344 | doi = 10.1016/0165-6147(96)10005-5 }} 3. ^1 {{cite journal |vauthors=Sugden D, Davidson K, Hough KA, Teh MT | title = Melatonin, melatonin receptors and melanophores: a moving story | journal = Pigment Cell Res. | volume = 17 | issue = 5 | pages = 454–60 | year = 2004 | pmid = 15357831 | doi = 10.1111/j.1600-0749.2004.00185.x }} 4. ^{{cite journal |vauthors=Morgan PJ, Barrett P, Howell HE, Helliwell R | title = Melatonin receptors: localization, molecular pharmacology and physiological significance | journal = Neurochem. Int. | volume = 24 | issue = 2 | pages = 101–46 | year = 1994 | pmid = 8161940 | doi = 10.1016/0197-0186(94)90100-7 }} 5. ^1 {{cite journal |vauthors=Reppert SM, Godson C, Mahle CD, Weaver DR, Slaugenhaupt SA, Gusella JF | title = Molecular characterization of a second melatonin receptor expressed in human retina and brain: the Mel1b melatonin receptor | journal = Proc. Natl. Acad. Sci. U.S.A. | volume = 92 | issue = 19 | pages = 8734–38 |date=September 1995 | pmid = 7568007 | pmc = 41041 | doi = 10.1073/pnas.92.19.8734| bibcode = 1995PNAS...92.8734R }} 6. ^{{cite journal |vauthors=Besharse JC, Dunis DA | title = Methoxyindoles and photoreceptor metabolism: activation of rod shedding | journal = Science | volume = 219 | issue = 4590 | pages = 1341–43 |date=March 1983 | pmid = 6828862 | doi = 10.1126/science.6828862| bibcode = 1983Sci...219.1341B }} 7. ^{{cite journal |vauthors=Sharan K, Lewis K, Furukawa T, Yadav VK |title=Regulation of bone mass through pineal-derived melatonin-MT2 pathway |journal=J Pineal Res |pmid=28512916 |doi= 10.1002/jbm.a.30786}} 8. ^{{cite journal |vauthors=Nickelsen T, Samel A, Vejvoda M, Wenzel J, Smith B, Gerzer R | title = Chronobiotic effects of the melatonin agonist LY 156735 following a simulated 9h time shift: results of a placebo-controlled trial | journal = Chronobiol. Int. | volume = 19 | issue = 5 | pages = 915–36 |date=September 2002 | pmid = 12405554 | doi = 10.1081/cbi-120014108}} External links
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