Dopamine effects on neuromuscular function in hyperthermia

我们实验室的主要研究重点是人体在极端温度下的功能。在这个领域，一个重要的问题是，为什么人类在炎热的环境中不能像在凉爽的环境中那样努力或长时间地运动。从历史上看，这种情况的主要观点被认为是出汗导致的液体流失使心脏工作更加困难。然而，在过去的二十年里，许多其他的新想法被提出和证明，包括我们的实验室表明，即使皮肤或肌肉本身保持凉爽，热的大脑也无法招募和激活肌肉。从那以后，我们通过观察脑血流量或脑血化学来进一步研究这一点，这两者都可能随着体温升高而改变，从而影响肌肉功能。

Our lab has a main research focus on how the human body functions during extreme temperatures. In this field, an important question is why humans cannot exercise as hard or for as long in hot compared to cooler conditions. Historically, the main idea for this is suggested to be the loss of fluid through sweating making the heart work harder. However, many other new ideas have been proposed and demonstrated over the last twenty years, including our lab showing that a hot brain is less able to recruit and activate muscles, even if the skin or muscle itself is kept cool. We have since studied this further by looking at how brain blood flow or brain blood chemistry, both of which may change with high body temperatures, can affect muscle function. Other labs have shown that higher levels of dopamine, a transmitter molecule in the brain that seems to increase mental arousal and also heat loss responses in the body, can cause fit athletes to exercise longer and harder in the heat, and also be able to tolerate higher body temperatures. However, we do not know how dopamine might affect muscle function in the heat. We also do not know whether dopamine may affect individuals differently depending on their fitness levels. Our proposal tests whether dopamine levels directly affects muscle function at high body temperatures in people with both high and low aerobic fitness, with the overall goal of better understanding how we maintain body temperature in situations of high heat stress.