Article

Reppert SM, Weaver DR, Cassone VM, et al. Melatonin receptor are for the birds: molecular analysis of two receptor subtypes differentially expressed in chick brain. Neuron 15: 1003-15

Laboratory of Developmental Chronobiology, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
Neuron (Impact Factor: 15.05). 12/1995; 15(5):1003-15. DOI: 10.1016/0896-6273(95)90090-X
Source: PubMed

ABSTRACT

Two receptors (CKA and CKB) of the G protein-coupled melatonin receptor family were cloned from chick brain. CKA encodes a protein that is 80% identical at the amino acid level to the human Mel1a melatonin receptor and is thus designated the chick Mel1a melatonin receptor. CKB encodes a protein that is 80% identical to the Xenopus melatonin receptor and defines a new receptor subtype, the Mel1c melatonin receptor, which is distinct from the Mel1a and Mel1b melatonin receptor subtypes. A melatonin receptor family consisting of three subtypes is supported by PCR cloning of distinct melatonin receptor fragments from Xenopus and zebrafish. Expression of CKA and CKB results in similar ligand binding and functional characteristics. The widespread distribution of CKA and CKB mRNA in brain provides a molecular substrate for the profound actions of melatonin in birds.

    • "The locations and pharmacology of melatonin receptors have recently been extensively reviewed. Two cloned receptors, MT1 and MT2 (Masana and Dubocovich, 2001;Reppert et al., 1995), are of particular importance with regard to rhythm physiology and pharmacology. Using gene knockout technology in mice and pharmacological manipulations, the results to date suggest that the phase-shifting melatonin receptor in the SCN is MT2, while MT1 is associated with acute suppression of SCN electrical activity (Liu et al., 1997). "
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    • "In addition, two subtypes of Mtnr1a, i.e. Mtnr1a1.4 (also known as Mel 1a 1.4) and Mtnr1a1.7 (also known as Mel 1a 1.7), have been identified in zebrafish, Danio rerio (Reppert et al., 1995), rainbow trout, Oncorhynchus mykiss (Mazurais et al., 1999), grass puffer, Takifugu niphobles (Ikegami et al., 2009b), and goldfish, Carassius auratus (Ikegami et al., 2009a). The mudskipper Boleophthalmus pectinirostris, a burrow-dwelling fish inhabiting intertidal mudflats, is an exceptional model among fishes for their amphibious behavior and numerous physiological and morphological specializations adapted for amphibious life (Chen et al., 2006, 2007; Hong et al., 2007, 2013). "
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    • "Melatonin may have direct and indirect effects. Most of the avian brain is sensitive to melatonin, as shown by the widespread distribution of melatonin receptors in almost all brain regions of several birds species [44-46] including Sylvia warblers (Fusani & Gahr, unpublished). Thus, it is conceivable the melatonin acts directly on some area to suppress (or reduce) Zugunruhe by influencing circadian oscillators [5,47]. "
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