title: Circadian behaviour in neuroglobin deficient mice.
abstract: Neuroglobin (Ngb), a neuron-specific oxygen-binding globin with an unknown function, has been proposed to play a key role in neuronal survival. We have previously shown Ngb to be highly expressed in the rat suprachiasmatic nucleus (SCN). The present study addresses the effect of Ngb deficiency on circadian behavior. Ngb-deficient and wild-type (wt) mice were placed in running wheels and their activity rhythms, endogenous period and response to light stimuli were investigated. The effect of Ngb deficiency on the expression of Period1 (Per1) and the immediate early gene Fos was determined after light stimulation at night and the neurochemical phenotype of Ngb expressing neurons in wt mice was characterized. Loss of Ngb function had no effect on overall circadian entrainment, but resulted in a significantly larger phase delay of circadian rhythm upon light stimulation at early night. A light-induced increase in Per1, but not Fos, gene expression was observed in Ngb-deficient mice. Ngb expressing neurons which co-stored Gastrin Releasing Peptide (GRP) and were innervated from the eye and the geniculo-hypothalamic tract expressed FOS after light stimulation. No PER1 expression was observed in Ngb-positive neurons. The present study demonstrates for the first time that the genetic elimination of Ngb does not affect core clock function but evokes an increased behavioural response to light concomitant with increased Per1 gene expression in the SCN at early night.
authors.affiliation: Department of Clinical Biochemistry, Faculty of Health Science, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Hundahl
authors.forename: Jan
authors.initials: J
authors.lastname: Fahrenkrug
authors.forename: Anders
authors.initials: A
authors.lastname: Hay-Schmidt
authors.forename: Birgitte
authors.initials: B
authors.lastname: Georg
authors.forename: Birgitte
authors.initials: B
authors.lastname: Faltoft
authors.forename: Jens
authors.initials: J
authors.lastname: Hannibal
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D015153:Blotting, Western; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005455:Fluorescent Antibody Technique; D005914:Globins / Q000502:physiology*; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D008027:Light; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009419:Nerve Tissue Proteins / Q000502:physiology*; D000078787:Neuroglobin; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000378:metabolism*; D013569:Synapses / Q000502:physiology
chemical_list: D009419:Nerve Tissue Proteins; D000078787:Neuroglobin; C539023:Per1 protein, mouse; D056950:Period Circadian Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D005914:Globins