title: Role of melanopsin in circadian responses to light.
abstract: Melanopsin has been proposed as an important photoreceptive molecule for the mammalian circadian system. Its importance in this role was tested in melanopsin knockout mice. These mice entrained to a light/dark cycle, phase-shifted after a light pulse, and increased circadian period when light intensity increased. Induction of the immediate-early gene c-fos was observed after a nighttime light pulse in both wild-type and knockout mice. However, the magnitude of these behavioral responses in knockout mice was 40% lower than in wild-type mice. Although melanopsin is not essential for the circadian clock to receive photic input, it contributes significantly to the magnitude of photic responses.
authors.affiliation: Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. ruby@stanford.edu
authors.forename: Norman F
authors.initials: NF
authors.lastname: Ruby
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Brennan
authors.forename: Xinmin
authors.initials: X
authors.lastname: Xie
authors.forename: Vinh
authors.initials: V
authors.lastname: Cao
authors.forename: Paul
authors.initials: P
authors.lastname: Franken
authors.forename: H Craig
authors.initials: HC
authors.lastname: Heller
authors.forename: Bruce F
authors.initials: BF
authors.lastname: O'Hara
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D003624:Darkness; D005260:Female; D005786:Gene Expression Regulation; D018390:Gene Targeting; D016762:Genes, fos; D017403:In Situ Hybridization; D008027:Light; D055537:Light Signal Transduction; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity; D012165:Retinal Ganglion Cells / Q000502:physiology; D017299:Rod Opsins / Q000235:genetics / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000502:physiology; D000099210:Melanopsin
chemical_list: D017299:Rod Opsins; D000099210:Melanopsin