| Phase and period responses of the jerboa Jaculus orientalis to short light pulses. | |
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MedLine Citation:
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PMID: 20795880 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The phase and period responses to short light pulses were studied in the jerboa, a seasonal, hibernating, nocturnal rodent from the Atlas region in Morocco. The jerboa, which is a saltatory species, showed precise activity onsets and offsets under a light-dark (LD) cycle using infrared captors to record locomotor activity. When released into constant darkness (DD), the majority of animals showed a circadian period (tau) < 24 h (mean tau = 23.89 +/- 0.13 h) and a lengthening of the activity span, alpha. Animals were subsequently exposed to up to eight 15-min light pulses, each separated by at least 2 wks, for up to 160 days in DD. During this span, most individuals maintained robust circadian rhythmicity, with clearly defined activity onsets and offsets, similar levels of total activity, duration of alpha, and percent activity occurring during the subjective night. The phase response curve (PRC) is typical of other nocturnal rodents, with light eliciting delays during late subjective day and early subjective night (CT8-CT19) and advances during late subjective night to early subjective day (CT19-CT2). A dead zone, when light had no effect on phase, is observed during mid-subjective day (CT3-CT8). A few individuals showed large (> 9 h) Type 0 phase resetting near the singularity region (CT19) that resulted in a complete phase reversal, but otherwise displayed normal phase-shifting responses at other CT times. The tau response curve showed a decrease in period from early to late subjective night with increases at other times, but these changes were small (maximum < 9 min) and highly variable. There was a distinct tendency for animals that had an initial short tau in DD to conserve a short tau during the series of light pulses and, inversely, for animals with long tau to conserve a long tau. This suggests possible constraints on the plasticity of variation of tau in relation to the endogenous period of the animal. |
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Authors:
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Rachid El Moussaouiti; Nezha Bouhaddou; Mariam Sabbar; Howard M Cooper; Nouria Lakhdar-Ghazal |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Chronobiology international Volume: 27 ISSN: 1525-6073 ISO Abbreviation: Chronobiol. Int. Publication Date: 2010 Aug |
Date Detail:
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Created Date: 2010-08-27 Completed Date: 2010-12-16 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8501362 Medline TA: Chronobiol Int Country: England |
Other Details:
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Languages: eng Pagination: 1348-64 Citation Subset: IM |
Affiliation:
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Equipe de Recherche sur les Rythmes Biologiques et Environnement (ERRBE), Faculte des Sciences, Université Mohammed V-Agdal, Rabat, Morocco. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Biological Clocks / physiology Circadian Rhythm / physiology* Darkness Light* Motor Activity / physiology Photoperiod* Rodentia / physiology* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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