Recent research at the University may have identified the specific neurotransmitter in the human body that regulates blood flow to the skin and controls body temperature, and the researchers hope to use the information to help patients with heart disease or other ailments that make their bodies unable to raise skin blood flow.
University Human Physiology Professor Christopher Minson and former University doctoral student Brett Wong worked together on the study, which was first published online Oct. 5.
Typically, the body’s temperature is raised by the increased blood flow to the surface of the skin, caused by either exercise or outside influence. The body responds by sweating to cool back down. If one or both of those mechanisms is not working, Minson said, the body would not be able to function efficiently at all.
“This is a very important response to humans,” Minson said. “It is the reason why we are able to adjust to our environment so well.”
Minson said many older people are unable to naturally regulate their body temperatures.
Wong wrote in an e-mail that the research is an important step toward helping those who may be unable to adequately regulate blood flow because of illness.
“We need to understand how this system works in young, healthy subjects before we can help those populations who are most at risk for heat-related illnesses and death,” he said.
Gary Klug, head of the human physiology department, said the research could also be applied to athletes, who must consider body temperature in competition and training.
“This has not only applications to medical conditions, but it also has ramifications for people who wish to maximize performance,” Klug said.
Klug added that the study fits well into the Human Physiology Department’s goal of expanding basic science to clinical application.
Wong said this particular study took approximately a year and a half in the lab to complete.
Minson said he also hopes his work will lead to more discoveries down the line.
“I think basic science can’t be forgotten simply because when you find something that’s of value, so many other studies can come out of that,” he said.
The experiment used a neurotransmitter known as “substance P,” a natural biochemical that the body produces, to pin down the specific receptor known as neurokinin-receptor 1, or NK-1, in the body that controls blood flow to the skin.
To do this, Minson first gave subjects the neurotransmitter through fibers in the skin to activate the receptor and heighten blood flow to the skin. After this initial spike happens, Minson said, the receptor, called NK-1, is desensitized and doesn’t respond to the chemical anymore.
From there, Minson put subjects under a full body heat stress and monitored blood flow to see if the NK-1 receptor was indeed the one researchers were looking for.
“It’s kind of a unique approach at getting at removing those receptors,” Minson said.
Minson said the procedure only deactivates the NK-1 receptor for skin blood flow, and other receptors are unaffected.
Minson said the study suggested that NK-1 was the acting receptor in body temperature regulation.
“During that whole body heat stress, we found that the rise in skin blood flow was greatly reduced when we had knocked out that NK-1 receptor,” Minson said. “It wasn’t gone, but it was greatly reduced.”
In order to induce heat to the body, subjects donned a full body suit that pumped hot water through tubes inside it.
“It’s a pretty significant heat stress,” Minson said. “When we first turn it on people are like ‘Oh, it feels nice.’ It feels like you just kind of slipped into a Jacuzzi. But as the heat stress progresses, we don’t let you out of the Jacuzzi.”
Minson said the procedure was perfectly safe for the subjects.
Wong, a former doctoral student of Minson’s who is now a postdoctoral researcher at the University of Iowa, said the experiment was a continuation of past research he had done before collaborating with Minson. He also said there is much more work to be done for it to become more meaningful.
“It is important to realize that there are a number of conditions that can adversely affect one’s ability to regulate their body temperature in the heat, including cardiovascular disease, diabetes, and even healthy aging,” Wong said.
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