Mallette Matthew M, Hodges Gary J, McGarr Gregory W, Gabriel David A, Cheung Stephen S
Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, Canada.
Electromyographic Kinesiology Laboratory, Department of Kinesiology, Brock University, St. Catharines, Canada.
Microvasc Res. 2016 Jul;106:88-95. doi: 10.1016/j.mvr.2016.03.010. Epub 2016 Apr 9.
We sought to isolate the contributions of core and local temperature on forearm skin blood flow (SkBF), and to examine the interaction between local- and reflexive-mechanisms of SkBF control. Forearm SkBF was assessed using laser-Doppler flowmetry in eight males and eight females during normothermia and hyperthermia (+1.2°C rectal temperature). Mean experimental forearm temperature was manipulated in four, 5min blocks between neutral (A: 33.0°C) and warm (B: 38.5°C) in an A-B-A-B fashion during normothermia, and B-A-B-A during hyperthermia. Mean control forearm skin temperature was maintained at ~33°C. Finally, local heating to 44°C was performed on both forearms to elicit maximal SkBF. Data are presented as a percentage of maximal cutaneous vascular conductance (CVC), calculated as laser-Doppler flux divided by mean arterial pressure. No sex differences were observed in any CVC measures (P>0.05). During normothermia, increasing experimental forearm temperature to 38.5°C elevated CVC by 42±8%max (d=3.1, P<0.001). Subsequently decreasing experimental forearm temperature back down to 33.0°C reduced CVC by 36±7%max (d=2.5, P<0.001). Finally, the second increase in experimental forearm temperature to 38.5°C increased CVC by 25±6%max (d=1.9, P<0.0001). During hyperthermia, decreasing experimental forearm temperature to 33.0°C reduced CVC by 6±1%max (d=0.5, P<0.001). Increasing experimental forearm temperature to 38.5°C increased CVC by 4±2%max (d=0.4, P<0.001). Finally, decreasing experimental forearm temperature to 33.0°C reduced CVC by 8±2%max (d=0.7, P<0.001). Compared to normothermia, CVC responses to local temperature changes during hyperthermia were almost abolished (normothermia: d=1.9-3.1; hyperthermia: d=0.4-0.7). These data indicate that local temperature drives SkBF during normothermia, while reflexive mechanisms regulate SkBF during hyperthermia.
我们试图分离核心温度和局部温度对前臂皮肤血流量（SkBF）的影响，并研究SkBF控制的局部机制和反射机制之间的相互作用。在正常体温和体温过高（直肠温度+1.2°C）期间，使用激光多普勒血流仪对8名男性和8名女性的前臂SkBF进行评估。在正常体温期间，以A-B-A-B的方式在四个5分钟的时间段内将实验前臂的平均温度在中性（A：33.0°C）和温暖（B：38.5°C）之间进行调节，在体温过高期间则以B-A-B-A的方式进行调节。将对照前臂皮肤的平均温度维持在约33°C。最后，对双侧前臂进行局部加热至44°C以引发最大SkBF。数据以最大皮肤血管传导率（CVC）的百分比表示，计算方法为激光多普勒通量除以平均动脉压。在任何CVC测量中均未观察到性别差异（P>0.05）。在正常体温期间，将实验前臂温度升高至38.5°C可使CVC升高42±8%max（d=3.1，P<0.001）。随后将实验前臂温度降低回33.0°C可使CVC降低36±7%max（d=2.5，P<0.001）。最后，将实验前臂温度再次升高至38.5°C可使CVC升高25±6%max（d=1.9，P<0.0001）。在体温过高期间，将实验前臂温度降低至33.0°C可使CVC降低6±1%max（d=0.5，P<0.001）。将实验前臂温度升高至38.5°C可使CVC升高4±2%max（d=0.4，P<0.001）。最后，将实验前臂温度降低至33.0°C可使CVC降低8±2%max（d=0.7，P<0.001）。与正常体温相比，体温过高期间CVC对局部温度变化的反应几乎完全消失（正常体温：d=1.9-3.1；体温过高：d=0.4-0.7）。这些数据表明，在正常体温期间局部温度驱动SkBF，而在体温过高期间反射机制调节SkBF。
