Nagasaka T, Cabanac M, Hirata K, Nunomura T
Pflugers Arch. 1986 Jul;407(1):71-5. doi: 10.1007/BF00580723.
This study examined the effect of local heating on the blood flow of the finger or forearm in male subjects in an environment of 35 degrees C--40% (r.h.). One hand or forearm was immersed in a water bath the temperature of which (Tw) was raised by 1 degrees C every 10th min from 35 degrees to 43 degrees C, while the other hand or forearm was kept at a constant Tw of 35 degrees C. Blood-flow (BF) was measured by venous occlusion plethysmography, using temperature-compensated mercury-in-Silastic strain gauges. Finger BF in the heated hand was significantly lower than that in the control hand at TwS of 37 degrees -41 degrees C, mostly for the first few minutes of each heating period. Thereafter, finger BF in the heated hand gradually returned toward the previous values. At TwS of 39 degrees -40 degrees C, however, finger BF in the heated hand remained lower than the control values for the entire period of heating. At TwS of 42 degrees -43 degrees C, finger BF in the heated hand greatly increased after an initial transitory fall. In the forearm skin, however, no such vasoconstriction in response to local heating was observed. All this suggests that a rise in skin temperature to above the core temperature produces paradoxical vasoconstriction in the finger, which may be a mechanism to reduce heat gain through the hand heated locally at higher temperatures.
本研究在35摄氏度、相对湿度40%的环境中，检测了局部加热对男性受试者手指或前臂血流的影响。将一只手或前臂浸入水温（Tw）每10分钟升高1摄氏度、从35摄氏度升至43摄氏度的水浴中，而另一只手或前臂保持在35摄氏度的恒定水温下。使用温度补偿的硅橡胶汞应变仪，通过静脉阻断体积描记法测量血流量（BF）。在37摄氏度至41摄氏度的水温下，受热手的手指BF明显低于对照手，主要出现在每个加热期的最初几分钟。此后，受热手的手指BF逐渐恢复到先前的值。然而，在39摄氏度至40摄氏度的水温下，受热手的手指BF在整个加热期间仍低于对照值。在42摄氏度至43摄氏度的水温下，受热手的手指BF在最初短暂下降后大幅增加。然而，在前臂皮肤中，未观察到对局部加热的这种血管收缩反应。所有这些表明，皮肤温度升高至高于核心温度会在手指中产生反常的血管收缩，这可能是一种减少通过在较高温度下局部受热的手部获得热量增加的机制。
