Sullivan R M, Wilson D A, Leon M
Department of Psychobiology, University of California, Irvine 92717.
Dev Psychobiol. 1988 Apr;21(3):237-50. doi: 10.1002/dev.420210305.
Previous work indicated that physical stimulation, such as that which mimics the stimulation pups receive from the dam, reduces pup body temperature. The present paper reports that the body and brain temperature of 5-day-old pups covaried under steady-state thermal conditions, cold exposure, and warmth exposure (Expt. 1) suggesting that body thermoregulatory mechanisms may also regulate brain temperature. Indeed, physically stimulating pups decreased brain temperature in the neocortex (Expt. 2) and the olfactory bulb (Expt. 3). The mechanism for this brain temperature decrease appears to be an increase in ventilatory heat exchange, the same mechanism responsible for the decrease in body temperature. Pups increased respiration during stimulation, thereby increasing air flow to the lungs where convective and evaporative heat exchange occurred. Indeed, stimulating pups in a high-humidity environment blocked the decrease in brain temperature (Expt. 4). The ability of physical stimulation to decrease brain temperature appears to be limited to neonatal pups, as 10-, 15-, and 20-day-old pups did not exhibit a brain temperature decrease in response to stimulation (Expt. 5).
先前的研究表明，物理刺激，如模拟幼崽从母鼠那里获得的刺激，会降低幼崽的体温。本文报道，在稳态热条件、冷暴露和暖暴露下，5日龄幼崽的身体和大脑温度存在协变关系（实验1），这表明身体的体温调节机制也可能调节大脑温度。事实上，对幼崽进行物理刺激会降低新皮层（实验2）和嗅球（实验3）的大脑温度。大脑温度降低的机制似乎是通气热交换增加，这与导致体温降低的机制相同。幼崽在刺激过程中呼吸增加，从而增加了流向肺部的气流，在肺部发生对流和蒸发热交换。事实上，在高湿度环境中刺激幼崽会阻止大脑温度的降低（实验4）。物理刺激降低大脑温度的能力似乎仅限于新生幼崽，因为10日龄、15日龄和20日龄的幼崽在受到刺激时并未出现大脑温度降低的情况（实验5）。
