Document Detail

Accelerated re-entrainment to advanced light cycles in BALB/cJ mice.
MedLine Citation:
PMID:  19619568     Owner:  NLM     Status:  MEDLINE    
Circadian rhythms in mammals are coordinated by the suprachiasmatic nuclei (SCN) of the hypothalamus, which are most potently synchronized to environmental light-dark cycles. Large advances in the light-dark cycle typically yield gradual advances in activity rhythms on the order of 1-2h per day until re-entrainment is complete due to limitations on the circadian system which are not yet understood. In humans, this delay until re-entrainment is accomplished is experienced as jetlag, with accompanying symptoms of malaise, decreased cognitive performance, sleep problems and gastrointestinal distress. In these experiments, locomotor rhythms of BALB/cJ mice monitored by running wheels were shown to re-entrain to large 6- or 8-hour shifts of the light-dark cycle within 1-2 days, as opposed to the 5-7 days required for C57BL/6J mice. A single-day 6-hour advance of the LD cycle followed by release to constant darkness yielded similar phase shifts, demonstrating that exaggerated re-entrainment is not explained by masking of activity by the light-dark cycle. Responses in BALB/cJ mice were similar when monitored instead by motion detectors, indicating that wheel-running exercise does not influence the magnitude of responses. Neither brief (15 min) light exposure late during subjective nighttime nor 6-hour delays of the light-dark cycle produced exaggerated locomotor phase shifts, indicating that BALB/cJ mice do not merely experience enhanced sensitivity to light. Fos protein was expressed in cells of the SCN following acute light exposure at ZT10 of their previous light-dark cycle, a normally non-responsive time in the circadian cycle, but only in BALB/cJ (and not C57BL/6J) mice that had been subjected two days earlier to a single-day 6-hour advance of the light-dark cycle, indicating that their SCN had been advanced by that treatment. BALB/cJ mice may thus serve as a useful comparative model for studying molecular and physiological processes that limit responsiveness of circadian clocks to photic input.
Tara A Legates; Danielle Dunn; E Todd Weber
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Publication Detail:
Type:  Journal Article     Date:  2009-07-17
Journal Detail:
Title:  Physiology & behavior     Volume:  98     ISSN:  1873-507X     ISO Abbreviation:  Physiol. Behav.     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-09-18     Completed Date:  2009-12-09     Revised Date:  2013-06-02    
Medline Journal Info:
Nlm Unique ID:  0151504     Medline TA:  Physiol Behav     Country:  United States    
Other Details:
Languages:  eng     Pagination:  427-32     Citation Subset:  IM    
Rider University, Lawrenceville, NJ 08648, USA.
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MeSH Terms
Analysis of Variance
Behavior, Animal
Circadian Rhythm / physiology
Gene Expression Regulation / physiology
Locomotion / physiology
Mice, Inbred BALB C
Mice, Inbred C57BL
Photic Stimulation
Proto-Oncogene Proteins c-fos / metabolism
Species Specificity
Suprachiasmatic Nucleus / metabolism
Time Factors
Grant Support
R15 NS054761-01/NS/NINDS NIH HHS
Reg. No./Substance:
0/Proto-Oncogene Proteins c-fos

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