Document Detail

Telemetry provides new insights into entrainment of activity wheel circadian rhythms and the role of body temperature in the development of ulcers in the activity-stress paradigm.
MedLine Citation:
PMID:  12435213     Owner:  NLM     Status:  MEDLINE    
Two methods of monitoring the circadian rhythm of activity in rodents: (1) an activity wheel cage, which detects the number of wheel revolutions, and (2) an internal radio transmitter, which records gross motor activity (GMA) of the animal, were compared in both normal circadian cycles and during the development of activity-stress ulcers. Rats were implanted with a biotelemetry transmitter that detected GMA and body temperature (BT) and placed in activity wheel cages. A 12 hour/12 hour light/dark cycle was maintained throughout the experiment. Subjects were subdivided into two groups: (1) unlimited access to activity wheel (AW) cages and (2) locked activity wheel (LW) cages. Following an ad-libitum habituation period, animals were allowed food access for 1 hour/day during the light. In the habituation period, the animals showed higher GMA and BT during the dark phase when housed in AW cages than in LW cages. Both GMA and number of wheel revolutions increased dramatically after the onset of food restriction for the AW animals. There was a deleterious drop in BT in AW animals as the food-restricted period continued and a significant correlation existed between severity of ulcerations and BT. The findings of this experiment demonstrate that the activity wheel imposes an alternation of the circadian cycle, which, in turn, influences rhythmicity through reentrainment. Additionally, in the activity-stress paradigm, a significant drop in BT correlates with severity of ulcerations. A disrupted circadian cycle, involving hypothermia, is proposed as the mechanism underlying the demise of animals in the activity-stress paradigm.
Helen M Murphy; Cyrilla H Wideman; Louise A Aquila; George R Nadzam
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Integrative physiological and behavioral science : the official journal of the Pavlovian Society     Volume:  37     ISSN:  1053-881X     ISO Abbreviation:  Integr Physiol Behav Sci     Publication Date:    2002 Jul-Sep
Date Detail:
Created Date:  2002-11-18     Completed Date:  2003-04-07     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9105843     Medline TA:  Integr Physiol Behav Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  228-41     Citation Subset:  IM    
Department of Psychology, John Carroll University, Cleveland, OH, 44118, USA.
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MeSH Terms
Body Temperature / physiology*
Circadian Rhythm / physiology*
Food Deprivation
Motor Activity / physiology*
Rats, Long-Evans
Stomach Ulcer / physiopathology*
Stress, Physiological / complications*
Telemetry / instrumentation*

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