title: Constant light enhances synchrony among circadian clock cells and promotes behavioral rhythms in VPAC2-signaling deficient mice.
abstract: Individual neurons in the suprachiasmatic nuclei (SCN) contain an intracellular molecular clock and use intercellular signaling to synchronize their timekeeping activities so that the SCN can coordinate brain physiology and behavior. The neuropeptide vasoactive intestinal polypeptide (VIP) and its VPAC2 receptor form a key component of intercellular signaling systems in the SCN and critically control cellular coupling. Targeted mutations in either the intracellular clock or intercellular neuropeptide signaling mechanisms, such as VIP-VPAC2 signaling, can lead to desynchronization of SCN neuronal clocks and loss of behavioral rhythms. An important goal in chronobiology is to develop interventions to correct deficiencies in circadian timekeeping. Here we show that extended exposure to constant light promotes synchrony among SCN clock cells and the expression of ~24 h rhythms in behavior in mice in which intercellular signaling is disrupted through loss of VIP-VPAC2 signaling. This study highlights the importance of SCN synchrony for the expression of rhythms in behavior and reveals how non-invasive manipulations in the external environment can be used to overcome neurochemical communication deficits in this important brain system.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester, UK.
authors.forename: Alun T L
authors.initials: AT
authors.lastname: Hughes
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester, UK.
authors.forename: Cara L
authors.initials: CL
authors.lastname: Croft
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester, UK.
authors.forename: Rayna E
authors.initials: RE
authors.lastname: Samuels
authors.affiliation: RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors.forename: Jihwan
authors.initials: J
authors.lastname: Myung
authors.affiliation: RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Takumi
authors.affiliation: Faculty of Life Sciences, University of Manchester, Manchester, UK.
authors.forename: Hugh D
authors.initials: HD
authors.lastname: Piggins
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D057906:Circadian Clocks / Q000235:genetics* / Q000528:radiation effects*; D002940:Circadian Rhythm / Q000235:genetics* / Q000528:radiation effects*; D008027:Light; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000378:metabolism / Q000528:radiation effects; D005082:Physical Exertion / Q000235:genetics / Q000528:radiation effects; D051239:Receptors, Vasoactive Intestinal Peptide, Type II / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D013493:Suprachiasmatic Nucleus / Q000378:metabolism / Q000528:radiation effects
chemical_list: D051239:Receptors, Vasoactive Intestinal Peptide, Type II