大绒鼠和高山姬鼠的体温调节和产热特征的季节性差异

Eothenomys miletus and Apodemus chevrieri are typical species of small mammals inhabiting in Hengduan mountains region. We tested their characteristics of thermoregulation and thermogenesis to search their physiological and ecological characteristics of adaptations to this region in different seasons. Metabolic rates were measured using closed-circuit respirometer and the nonshivering thermogenesis(NST) was induced by subcutaneous injection of norepinephrine. Results indicated: the body weight of Eothenomys miletus and Apodemus chevrieri in summer was separately 47.29±0.73g, 32.74±0.54g, and their body weight in winter was separately 39.28±0.61g, 31.70±0.76g; the thermal neutral zones(TNZ) of Eothenomys miletus and Apodemus chevrieri in summer were separately 25～32.5℃ and 25～30℃, and their TNZ in winter were 22.5～27.5℃; average body temperatures in summer were respectively 35.92±0.37℃ and 36.01±0.83℃, and their average body temperatures in winter were respectively 34.9±0.07℃、35.8±0.03℃; their basal metabolic rates(BMR) in summer were respectively 3.76± 0.07ml O2/g.h, 4.58±0.09mlO2/g.h, and their BMR in winter were respectively 4.46±0.04mlO2/g.h, 5.23±0.01mlO2/g.h; their maximum nonoshivering thermogenesis(NSTmax) in summer was respectively 5.70±0.18mlO2/g.h, 7.12±0.31mlO2/g.h, and their NSTmax in winter was respectively 6.67±0.05mlO2/g.h, 7.42±0.04mlO2/g.h; their NST scope(NSTmax/BMR) in summer was separately 1.52±0.05, 1.46±0.04, and their NST scope in winter was separately 1.49±0.01, 1.42±0.01. Their thermogenic characteristics and thermoregulatory styles possibly reflected features of small rodents in Hengduan mountains region which have lower body temperatures and NST scope, higher BMR, Cm and NSTmaxand could keep their body temperatures stable in narrower ambient temperatures comparing with other rodents. Body temperature, Cm BMR and NSTmax of Apodemus chevrieri were higher than these of Eothenomys miletus. Apodemus chevrieri could keep body temperature stable in a wider range of ambient temperatures than Eothenomys miletus. NST scope of Eothenomys miletus was higher than it of Apodemus chevrieri. Their TNZ and the ambient temperature range in which they could keep C stable in winter were narrower than their these indexes in summer. Their body temperature and body weight in winter were lower comparing with the summer. Their BMR, F-value and NSTmax in winter were significantly higher than the summer. Their TNZ in winter was shifted to the lower ambient temperature comparing with the summer. There was not significant difference in their NST scope and C of the summer and winter.