title: Aging alters circadian and light-induced expression of clock genes in golden hamsters.
abstract: Aging alters numerous aspects of circadian biology, including the amplitude of rhythms generated by the suprachiasmatic nuclei (SCN) of the hypothalamus, the site of the central circadian pacemaker in mammals, and the response of the pacemaker to environmental stimuli such as light. Although previous studies have described molecular correlates of these behavioral changes, to date only 1 study in rats has attempted to determine if there are age-related changes in the expression of genes that comprise the circadian clock itself. We used in situ hybridization to examine the effects of age on the circadian pattern of expression of a subset of the genes that comprise the molecular machinery of the circadian clock in golden hamsters. Here we report that age alters the 24-h expression profile of Clock and its binding partner Bmal1 in the hamster SCN. There is no effect of age on the 24-h profile of either Per1 or Per2 when hamsters are housed in constant darkness. We also found that light pulses, which induce smaller phase shifts in old animals than in young, lead to decreased induction of Per1, but not of Per2, in the SCN of old hamsters.
authors.affiliation: Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA. kolkerd@mail.nih.gov
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Kolker
authors.forename: Hiroo
authors.initials: H
authors.lastname: Fukuyama
authors.forename: David S
authors.initials: DS
authors.lastname: Huang
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Takahashi
authors.forename: Teresa H
authors.initials: TH
authors.lastname: Horton
authors.forename: Fred W
authors.initials: FW
authors.lastname: Turek
mesh_terms: D056930:ARNTL Transcription Factors; D000375:Aging / Q000235:genetics* / Q000502:physiology*; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology*; D003001:Cloning, Molecular; D006224:Cricetinae; D017931:DNA Primers; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D015870:Gene Expression / Q000235:genetics* / Q000502:physiology*; D017403:In Situ Hybridization; D008027:Light; D008647:Mesocricetus; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics; D056950:Period Circadian Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D009687:Nuclear Proteins; D056950:Period Circadian Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C538961:Bmal1 protein, mouse; C513312:Per2 protein, mouse; C538944:Clock protein, mouse; C538945:Clock protein, rat