title: Melatonin signaling modulates clock genes expression in the mouse retina.
abstract: Previous studies have shown that retinal melatonin plays an important role in the regulation of retinal daily and circadian rhythms. Melatonin exerts its influence by binding to G-protein coupled receptors named melatonin receptor type 1 and type 2 and both receptors are present in the mouse retina. Earlier studies have shown that clock genes are rhythmically expressed in the mouse retina and melatonin signaling may be implicated in the modulation of clock gene expression in this tissue. In this study we determined the daily and circadian expression patterns of Per1, Per2, Bmal1, Dbp, Nampt and c-fos in the retina and in the photoreceptor layer (using laser capture microdissection) in C3H-f+/+ and in melatonin receptors of knockout (MT1 and MT2) of the same genetic background using real-time quantitative RT-PCR. Our data indicated that clock and clock-controlled genes are rhythmically expressed in the retina and in the photoreceptor layer. Removal of melatonin signaling significantly affected the pattern of expression in the retina whereas in the photoreceptor layer only the Bmal1 circadian pattern of expression was affected by melatonin signaling removal. In conclusion, our data further support the notion that melatonin signaling may be important for the regulation of clock gene expression in the inner or ganglion cells layer, but not in photoreceptors.
authors.affiliation: Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States of America.
authors.forename: Susumu
authors.initials: S
authors.lastname: Hiragaki
authors.affiliation: Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
authors.forename: Kenkichi
authors.initials: K
authors.lastname: Baba
authors.affiliation: Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States of America.
authors.forename: Elise
authors.initials: E
authors.lastname: Coulson
authors.affiliation: Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States of America; Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kunst
authors.affiliation: Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University, Mainz, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Spessert
authors.affiliation: Neuroscience Institute and Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia, United States of America.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tosini
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D055786:Gene Knockout Techniques; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D051379:Mice; D010786:Photoreceptor Cells / Q000166:cytology / Q000378:metabolism; D044094:Receptors, Melatonin / Q000172:deficiency / Q000235:genetics; D012160:Retina / Q000166:cytology* / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D044094:Receptors, Melatonin; D008550:Melatonin