| Pacemaker phase control versus masking by light: setting the circadian chronotype in dual Octodon degus. | |
| | |
MedLine Citation:
|
PMID: 20795881 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
There are two main processes involved in the expression of circadian rhythmicity: entrainment and masking. Whereas the first operates via the central pacemaker to anticipate predictable environmental conditions, masking (mainly induced by light) functions as a direct modulator of the circadian output signal induced by nonpredictable events. The Chilean rodent Octodon degus presents both diurnal and nocturnal chronotypes when given free access to an exercise wheel. Two steady-entrainment phases and graded masking by light seem to generate the wide variability of chronotypes in this species. The aim of this study was to characterize the differential masking by light according to the individual chronotypes, their stability over time, and the influence of wheel running availability and ambient temperature upon the degus' nocturnality. To this end, diurnal and nocturnal degus were subjected to ultradian cycles (1:1-h light-dark [LD]), with and without wheel running availability, and under both normal and high diurnal ambient temperature cycles. The present results show that diurnal and nocturnal degus present a stable masking by light, each according to its respective chronotype. Thus, whereas diurnal animals increased their activity with light, in nocturnal degus light induced a sharp drop in wheel running activity. These two types of masking responses appeared not only when the animals were synchronized to the 12:12-h LD cycle, but also under ultradian cycles. Different masking effects persisted when wheel running was made unavailable and when the animals shifted their circadian activity patterns in response to ultradian cycles or to diurnal exposure to high temperatures. In conclusion, our results show that the positive and negative masking effects of light on diurnal and nocturnal degus, respectively, seem to occur independently of relative phase control by the central pacemaker or the negative masking induced by high environmental temperatures. |
| | |
Authors:
|
Pablo Vivanco; Maria Angeles Rol; Juan Antonio Madrid |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: Chronobiology international Volume: 27 ISSN: 1525-6073 ISO Abbreviation: Chronobiol. Int. Publication Date: 2010 Aug |
Date Detail:
|
Created Date: 2010-08-27 Completed Date: 2010-12-16 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 8501362 Medline TA: Chronobiol Int Country: England |
Other Details:
|
Languages: eng Pagination: 1365-79 Citation Subset: IM |
Affiliation:
|
Chronobiology Laboratory, Department of Physiology, Faculty of Biology University of Murcia, Murcia, Spain. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Biological Clocks / physiology* Circadian Rhythm / physiology* Female Light* Male Octodon / physiology* Photoperiod Temperature |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Phase and period responses of the jerboa Jaculus orientalis to short light pulses.
Next Document: Feeding entrainment of food-anticipatory activity and per1 expression in the brain and liver of zebr...