Effects of fasting on thermoregulatory processes and the daily oscillations in rats
Effects of fasting on thermoregulatory processes and the daily oscillations in rats
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DOI：
10.1152/ajpregu.00515.2002
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发表时间：
2003-06-01
影响因子：
2.8
通讯作者：
Kanosue, K
中科院分区：
文献类型：
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作者：
Nagashima, K;Nakai, S;Kanosue, K
为探讨大鼠禁食时体温(T-core)下降的机制，采用生物遥测法、红外热像仪和间接量热法，分别在禁食第3天和恢复后第4天，用生物遥测法、红外热像仪和间接量热法测定了禁食对照动物和禁食动物在23℃环境温度下的体温、体表温度和耗氧率。禁食当天，1)光期T核较对照降低(P<；0.05)，而暗期T核无变化，2)尾部温度较对照降低(P<；0.05，暗期从30.7±0.1℃降至23.9±0.1℃，光期从29.4±0.1℃降至25.2±0.2℃)，3)耗氧率较对照降低(P<；0.05，由24.37±1.06升至16.24±0.69毫升。分钟(-1)。暗期体重(-0.75)，18.91+/-0.64~14.00+/-0.41ml。分钟(-1)。Kg体质量(-0.75))。所有这些值在恢复当天都恢复到对照水平。结果表明，在禁食条件下，尽管代谢产热量减少，但通过抑制热损失机制，T-core仍保持在暗相。相反，在光相时，响应减弱，使T-core大大降低。此外，尾部血流调节的改变可能是抑制热损失的机制之一。
To investigate the mechanism involved in the reduction of body core temperature (T-core) during fasting in rats, which is selective in the light phase, we measured T-core, surface temperature, and oxygen consumption rate in fed control animals and in fasted animals on day 3 of fasting and day 4 of recovery at an ambient temperature (T-a) of 23 degreesC by biotelemetry, infrared thermography, and indirect calorimetry, respectively. On the fasting day, 1) T-core in the light phase decreased (P < 0.05) from the control; however, T-core in the dark phase was unchanged, 2) tail temperature fell from the control (P < 0.05, from 30.7 +/- 0.1 to 23.9 +/- 0.1 degreesC in the dark phase and from 29.4 +/- 0.1 to 25.2 +/- 0.2 degreesC in the light phase), 3) oxygen consumption rate decreased from the control ( P < 0.05, from 24.37 +/- 1.06 to 16.24 +/- 0.69 ml . min(-1) . kg body wt(-0.75) in the dark phase and from 18.91 +/- 0.64 to 14.00 +/- 0.41 ml . min(-1) . kg body wt(-0.75) in the light phase). All these values returned to the control levels on the recovery day. The results suggest that, in the fasting condition, T-core in the dark phase was maintained by suppression of the heat loss mechanism, despite the reduction of metabolic heat production. In contrast, the response was weakened in the light phase, decreasing T-core greatly. Moreover, the change in the regulation of tail blood flow was a likely mechanism to suppress heat loss.