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IMPROVED TEMPERATURE GRADIENT FOR MONITORING BEHAVIORAL THERMOREGULATION IN THE RAT
Citation:
Gordon, C., K. Lee, T. Chen, P. Killough, AND J. Ali. IMPROVED TEMPERATURE GRADIENT FOR MONITORING BEHAVIORAL THERMOREGULATION IN THE RAT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-91/305 (NTIS PB92124619).
Description:
Past studies have found that the laboratory rat placed In a temperature gradient prefers temperatures that are markedly below its lower critical ambient temperature (LCT), whereas other rodents (e.g., mouse, hamster, and guinea pig) generally select thermal environments associated with minimal metabolic expenditure. o further study the rat's thermoregulatory behavior, a temperature gradient was designed to monitor the selected ambient temperature (STa) and motor activity (MA) of rats of the Long-Evans (LE), Fischer 344 (F344), and Sprague-Dawley (SD) strains over a 22 hr period. he new gradient differs from previous systems in two ways: (i) it is larger permitting more unrestricted movements and (ii) it automatically monitors STa over a relatively long, uninterrupted period of time. ll three rat strains selected relatively cool STa's of 21 to 226 degrees C the first 1 to 3 hr in the temperature gradient. his was followed by a gradual increase in the STa which peaked at 4 (F344) to 6 hr (SD and LE) after being placed in the gradient. he LE strain had a significantly lower STa during the initial period in the gradient. here were slight decreases in the STa during the nocturnal phase in the F344 and SD strains concomitant with marked increases in MA.