The ability of our skin to let us know when it’s too warm is so well-known you likely don’t even think about it. What you may not have realized is that the molecular mechanism for this property, used for regulating body temperature, has been relatively unknown. Some new research out of the UK offers a possible discovery that a gene known as TRPM2 lets us know when warm temperatures are about.
Certain types of TRP (Transient Receptor Potential) proteins have previously been known to get triggered by painfully hot temperatures. This triggers a series of voltage changes within the sensory neurons of the skin and results in the appropriate (and painful) heat sensation. The pathways that triggered for milder, warm temperatures, however, were not previously revealed. It is this type of heat-activated gene that the researchers believe they have found.
The researchers isolated the TRPM2 pathway in mice and devised a way to turn the gene off. The mice with the inactive gene were then compared to those who still retained TRPM2 to see how they reacted. When made to walk across surfaces at either 33 or 38 degrees Celsius, the normal mice consistently preferred the cooler environment. When the mice with the removed TRPM2 were tested, the mice weren’t able to distinguish between the two areas. More tellingly was that the mice who had TRPM2 removed were still able to notice and react appropriately to painful levels of heat, further suggesting the gene only worked on detecting milder levels of warmth.
There is no immediate clinical potential for this finding, but it is still a neat discovery that will hopefully get confirmed and further explored. The impact of the TRPM2 gene on sensory neurons and the ability to detect warmth is a basic part of human behaviour, after all. If you have ever been in a stuffy car and rolled down a window or taken off a jacket, this finding suggests it was because of the messages you received from TRPM2 saying it was getting warm. Although the gene has been associated with perceptions of temperature, further research will be needed to see if it has any influence on how body heat is regulated as well.
“Can’t stand the heat? Study reveals how we work out if we’re too hot,” King’s College London web site, August 17, 2016; http://www.kcl.ac.uk/ioppn/news/records/2016/August/Cant-stand-the-heat-Study-reveals-how-we-work-out-if-were-too-hot.aspx, last accessed August 19, 2016.