Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Twenty-Four Hour Rhythms of Selected Ambient Temperature in Rat and Hamster.
Author Gordon, C. J. ;
CORP Author Health Effects Research Lab., Research Triangle Park, NC. Neurotoxicology Div.
Publisher c1993
Year Published 1993
Report Number EPA/600/J-93/103;
Stock Number PB93-175727
Additional Subjects Rats ; Hamsters ; Circadian rhythm ; Body temperature regulation ; Motor activity ; Animal behavior ; Graphs(Charts) ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB93-175727 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 08/23/1993
Collation 9p
The purpose of the study was to assess the effect of time of day on the behavioral thermoregulatory patterns of nocturnal rodents, the Long-Evans (LE) rat, Fischer 344 (F344) rat, and the golden hamster. Individual animals were placed in a temperature gradient for 4 days while selected ambient temperature (ST(sub a)) and motor activity (MA) were monitored. Food was provided at the cold and warm ends of the gradient and water was provided ad lib. All animals eventually showed a 24-h rhythm of ST(sub a) and MA characterized by a preference for cooler T(sub a)s during the dark period which coincided with an increase in MA. Both rat strains had ST(sub a)s of about 28 C during the light period that decreased to 22-24 C during the dark period. The F344 rat developed a ST(sub a) rhythm by the second day in the gradient, whereas the LE strain required 4 days. The hamster exhibited relatively warm ST(sub a)s of 32-33 C during the light period that decreased to 26-28 C during the dark period. The nocturnal preference for cooler ST(sub a)s contradicts a current concept of an elevation in set point of the thermoregulatory system. However, the data also suggest that behavioral and autonomic thermoregulatory effectors may operate independently in the control of night time elevations in body temperature. (Copyright (c) 1993 Pergamon Press Ltd.)