Effect of age on cold acclimation in rats: metabolic and behavioral responses.
Effect of age on cold acclimation in rats: metabolic and behavioral responses.
复制标题
年龄对大鼠冷适应的影响：代谢和行为反应。
DOI：
10.1152/ajpregu.1991.260.2.r284
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Duckles,SP
中科院分区：
文献类型：
--
作者：
Owen,TL;Spencer,RL;Duckles,SP
为了确定衰老是否影响大鼠对慢性冷暴露的代谢和行为反应，对8和22个月龄雄性Fischer 344大鼠在6周(6-10℃)冷暴露前后进行了研究。在整个驯化期间，在温跃层(7-37摄氏度的线性梯度)中定期测量体重、食物消耗、氧气消耗、体温和环境温度选择。在驯化之前，年龄组只在体重上存在显著差异。在驯化过程中，老年大鼠的死亡率和发病率低于10摄氏度。在10摄氏度以下驯化后，年轻和老年大鼠都选择了较低的环境温度(分别比驯化前低7摄氏度和5摄氏度)，而老年大鼠在温跃层中的体温下降幅度明显更大。两个年龄组在25摄氏度的冷习服下都增加了静息代谢率(年轻大鼠和老年大鼠分别增加了16.5%和10%)。这项研究表明，年轻大鼠和老年大鼠对寒冷习服的代谢和行为反应存在明显差异。慢性冷暴露对老年大鼠的体温调节功能是有害的，因为它在刺激老年大鼠的代谢率持续增加方面不如年轻大鼠有效，而且它会导致偏爱较凉爽的环境温度，导致热量损失增加和体温下降。
To determine whether senescence affects the metabolic and behavioral responses of rats to chronic cold exposure, 8- and 22-mo-old male Fischer 344 rats were studied before and after 6 wk of cold (6-10 degrees C) exposure. Measurements of body weight, food consumption, oxygen consumption, body temperature, and ambient temperature selection in a thermocline (7-37 degrees C linear gradient) were made at regular intervals throughout the acclimation period. Before acclimation, age groups differed significantly only by weight. During acclimation, older rats had increased mortality and morbidity below 10 degrees C. After acclimation at 10 degrees C, younger and older rats both selected cooler ambient temperatures (7 and 5 degrees C cooler than preacclimation, respectively), and older rats had a significantly greater decrease in body temperature in the thermocline. Both age groups increased resting metabolic rate at 25 degrees C with cold acclimation (16.5 and 10% increase for younger and older rats, respectively). This study indicates distinct differences in metabolic and behavioral responses of younger and older rats to cold acclimation. Chronic cold exposure is detrimental to thermoregulatory function in older rats, since it is not as effective in stimulating sustained increases in metabolic rate in older rats as in young adults and it leads to a preference for cooler ambient temperatures, resulting in increased heat loss and reduced body temperature.