Journal of Biological Rhythms

 

Advanced Search

Journal Navigation

Journal Home

Subscriptions

Archive

Contact Us

Table of Contents

Click here for more information

Sign In to gain access to subscriptions and/or personal tools.
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Saved Citations
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Request Reprints
Right arrow Add to My Marked Citations
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bittman, E. L.
Right arrow Articles by McKinley Brewer, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bittman, E. L.
Right arrow Articles by McKinley Brewer, J.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
Journal of Biological Rhythms, Vol. 22, No. 5, 425-431 (2007)
DOI: 10.1177/0748730407303925
© 2007 SAGE Publications

Circadian Organization oftau Mutant Hamsters: Aftereffects and Splitting

Eric L. Bittman

Department of Biology and Program in Neuroscience and Behavior, University of Massachusetts, Amherst, elb{at}bio.umass.edu

Mary K. Costello

Department of Biology and Program in Neuroscience and Behavior, University of Massachusetts, Amherst

Judy McKinley Brewer

Department of Biology and Program in Neuroscience and Behavior, University of Massachusetts, Amherst

Homozygous tau mutant ({tau}ss) hamsters show an extremely short (20 h) circadian period ({tau}) that is attributable to altered enzymatic activity of casein kinase 1{varepsilon}. It has been proposed that coupling of constituent circadian oscillators is strengthened in {tau}ss hamsters, explaining their tendency to show strong resetting after prolonged exposure to constant darkness. To evaluate further the circadian organization of {tau}ss hamsters, the authors assessed the extent of shortening of period as an aftereffect of exposure to light:dark cycles whose period (T) is 91% of {tau} and the ability of constant light to induce splitting. They find that {tau}ss hamsters show aftereffects comparable to wild types, indicating that normal CK1{varepsilon} activity is not required for T cycles to shorten {tau}. This finding also contradicts the proposal that circadian period is homeostatically conserved. However, the authors find that {tau}ss hamsters rarely show splitting in constant light. Furthermore, LL does not induce lengthening of {tau} or reduction of activity duration ({alpha}) in these mutants. The authors' findings support the conclusion that the {tau} mutation alters the coupling between constituent circadian oscillators.

Key Words: circadian aftereffect • splitting • tau mutant hamster • circadian period • casein kinase 1{varepsilon}


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?