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    Aberrant Gating of Photic Input to the Suprachiasmatic Circadian Pacemaker of Mice Lacking the VPAC2 Receptor

    Hughes, A. T. and Fahey, Briana and Cutler, D.J. and Coogan, Andrew and Piggins, Hugh D (2004) Aberrant Gating of Photic Input to the Suprachiasmatic Circadian Pacemaker of Mice Lacking the VPAC2 Receptor. Journal of Neuroscience Methods, 24 (14). pp. 3522-3526. ISSN 0165-0270

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    VIP acting via the VPAC(2) receptor is implicated as a key signaling pathway in the maintenance and resetting of the hypothalamic suprachiasmatic nuclei (SCN) circadian pacemaker; circadian rhythms in SCN clock gene expression and wheel-running behavior are abolished in mice lacking the VPAC(2) receptor (Vipr2(-/-)). Here, using immunohistochemical detection of pERK (phosphorylated extracellular signal-regulated kinases 1/2) and c-FOS, we tested whether the gating of photic input to the SCN is maintained in these apparently arrhythmic Vipr2(-/-) mice. Under light/dark and constant darkness, spontaneous expression of pERK and c-FOS in the wild-type mouse SCN was significantly elevated during subjective day compared with subjective night; no diurnal or circadian variation in pERK or c-FOS was detected in the SCN of Vipr2(-/-) mice. In constant darkness, light pulses given during the subjective night but not the subjective day significantly increased expression of pERK and c-FOS in the wild-type SCN. In contrast, light pulses given during both subjective day and subjective night robustly increased expression of pERK and c-FOS in the Vipr2(-/-) mouse SCN. Although photic stimuli activate intracellular pathways within the SCN of Vipr2(-/-) mice, they do not engage the core clock mechanisms. The absence of photic gating, together with the general lack of overt rhythms in circadian output, strongly suggests that the SCN circadian pacemaker is completely dysfunctional in the Vipr2(-/-) mouse.

    Item Type: Article
    Keywords: circadian; vasoactive intestinal polypeptide; mitogen-activated protein kinase; wheel running; entrainment; suprachiasmatic nuclei;
    Academic Unit: Assisting Living & Learning,ALL institute
    Faculty of Science and Engineering > Psychology
    Faculty of Science and Engineering > Research Institutes > Human Health Institute
    Item ID: 16466
    Identification Number:
    Depositing User: Dr. Andrew Coogan
    Date Deposited: 30 Aug 2022 15:48
    Journal or Publication Title: Journal of Neuroscience Methods
    Publisher: Elsevier
    Refereed: Yes
    Use Licence: This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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