title: Melanopsin (Opn4) requirement for normal light-induced circadian phase shifting.
abstract: The master circadian oscillator in the hypothalamic suprachiasmatic nucleus is entrained to the day/night cycle by retinal photoreceptors. Melanopsin (Opn4), an opsin-based photopigment, is a primary candidate for photoreceptor-mediated entrainment. To investigate the functional role of melanopsin in light resetting of the oscillator, we generated melanopsin-null mice (Opn4-/-). These mice entrain to a light/dark cycle and do not exhibit any overt defect in circadian activity rhythms under constant darkness. However, they display severely attenuated phase resetting in response to brief pulses of monochromatic light, highlighting the critical role of melanopsin in circadian photoentrainment in mammals.
authors.affiliation: Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA.
authors.forename: Satchidananda
authors.initials: S
authors.lastname: Panda
authors.forename: Trey K
authors.initials: TK
authors.lastname: Sato
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Castrucci
authors.forename: Mark D
authors.initials: MD
authors.lastname: Rollag
authors.forename: Willem J
authors.initials: WJ
authors.lastname: DeGrip
authors.forename: John B
authors.initials: JB
authors.lastname: Hogenesch
authors.forename: Ignacio
authors.initials: I
authors.lastname: Provencio
authors.forename: Steve A
authors.initials: SA
authors.lastname: Kay
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D003624:Darkness; D005260:Female; D018390:Gene Targeting; 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