Locomotor activity, core body temperature, and circadian rhythms in mice selected for high or low heat loss

摘要: Daily locomotor activity, core body temperature, and their circadian rhythms were measured in lines of mice selected for high (MH) or low (ML) heat loss unselected controls (MC). Lines created by selecting 16 generations each three replicates. Collection activity temperature data spanned Generations 20 21 a total 352 mice. Physical accumulated using implanted transmitters continuous automated collection. Measurement animal was 3 d. Activity recorded half hour then averaged the day; daily; rhythm expressed 12-h (light vs dark) 6-h periods as well fitting cyclic models. means transformed to log base 2 lessen heterogeneity variance within lines. Heat 15-h period beginning at 1630 feed intake 7 d on 74 additional order estimate relationship between intake. Selection different (P 0.38). Retransformed from scale measurement, mean counts 308, 210, 150 MH, MC, ML, respectively. Mean temperatures 37.2, 36.9, 36.7 degrees C ML 0.20). Overall phenotypic correlation 0.43 0.1) physical temperature. More sensitive models revealed significant < 0.01) 24-, 12-, 8-, cycles that differed among Estimated differences MH due 36 11.5%, Variation thus contributed variation