Melatonin receptor

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melatonin receptor 1A
Identifiers
Symbol MTNR1A
Entrez 4543
HUGO 7463
OMIM 600665
RefSeq NM_005958
UniProt P48039
Other data
Locus Chr. 4 q35.1
melatonin receptor 1B
Identifiers
Symbol MTNR1B
Entrez 4544
HUGO 7464
OMIM 600804
RefSeq NM_005959
UniProt P49286
Other data
Locus Chr. 11 q21-q22

A melatonin receptor is a G protein-coupled receptor (GPCR) which binds melatonin.[1]

Three types of melatonin receptor 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 patterns[edit]

In 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]

MT1[edit]

In humans, The MT1 subtype is expressed in the pars tuberalis of the pituitary gland and the suprachiasmatic nuclei of the hypothalamus.

MT2[edit]

The MT2 subtype is expressed in the retina. MT2 receptor mRNA has not been detected by in situ hybridization in the rat suprachiasmatic nucleo or pars tubealis.[5]

MT3[edit]

The MT3 subtype of many non-mammalian vertebrates is expressed in various brain areas.[3]

MT Receptor function[edit]

MT1[edit]

In humans, The MT1 subtype's expression in the pars tuberalis of the pituitary gland and suprachiamatic nuclei of the hypothalamus is indicative of melatonin's circadian and reproductive functional involvement.

MT2[edit]

In 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]

MT3[edit]

Selective Ligands[edit]

Agonists[edit]

Antagonists[edit]

See also[edit]

References[edit]

  1. ^ Reppert SM (1997). "Melatonin receptors: molecular biology of a new family of G protein-coupled receptors". J. Biol. Rhythms 12 (6): 528–31. doi:10.1177/074873049701200606. PMID 9406026. 
  2. ^ Reppert SM, Weaver DR, Godson C (1996). "Melatonin receptors step into the light: cloning and classification of subtypes". Trends Pharmacol. Sci. 17 (3): 100–2. doi:10.1016/0165-6147(96)10005-5. PMID 8936344. 
  3. ^ a b Sugden D, Davidson K, Hough KA, Teh MT (2004). "Melatonin, melatonin receptors and melanophores: a moving story". Pigment Cell Res. 17 (5): 454–60. doi:10.1111/j.1600-0749.2004.00185.x. PMID 15357831. 
  4. ^ Morgan PJ, Barrett P, Howell HE, Helliwell R (1994). "Melatonin receptors: localization, molecular pharmacology and physiological significance". Neurochem. Int. 24 (2): 101–46. doi:10.1016/0197-0186(94)90100-7. PMID 8161940. 
  5. ^ a b Reppert SM, Godson C, Mahle CD, Weaver DR, Slaugenhaupt SA, Gusella JF (September 1995). "Molecular characterization of a second melatonin receptor expressed in human retina and brain: the Mel1b melatonin receptor". Proc. Natl. Acad. Sci. U.S.A. 92 (19): 8734–8. Bibcode:1995PNAS...92.8734R. doi:10.1073/pnas.92.19.8734. PMC 41041. PMID 7568007. 
  6. ^ Besharse JC, Dunis DA (March 1983). "Methoxyindoles and photoreceptor metabolism: activation of rod shedding". Science 219 (4590): 1341–3. Bibcode:1983Sci...219.1341B. doi:10.1126/science.6828862. PMID 6828862. 
  7. ^ Nickelsen T, Samel A, Vejvoda M, Wenzel J, Smith B, Gerzer R (September 2002). "Chronobiotic effects of the melatonin agonist LY 156735 following a simulated 9h time shift: results of a placebo-controlled trial". Chronobiol. Int. 19 (5): 915–36. PMID 12405554. 

External links[edit]