Neuroscientists at the University of Michigan have identified thermoreceptors that mediate the sensation of cold in somatosensory neurons.
“The field began elucidating such temperature sensors more than 20 years ago with the discovery of a heat-sensing protein called TRPV1,” said Professor Sean Hsu of the University of Michigan.
“While various studies have discovered proteins that sense hot, warm, and even cold temperatures, we have not identified any proteins that sense temperatures below about 15 degrees Celsius (60 degrees Fahrenheit).”
In 2019, scientists discovered The world's first cold receptor protein Caenorhabditis elegans a millimeter-long nematode species that the lab is studying as a model system for understanding sensory responses.
Because the gene that codes for it is Caenorhabditis elegans This protein is evolutionarily conserved across many species, including mice and humans, and this discovery was a starting point for testing cold sensors in mammals. Glutamate ion channel receptor kainate type subunit 2 (GluK2).
In a new study, Professor Xu and colleagues tested that hypothesis in mice with the deficiency. GluK2 Because of the gene, the GluK2 protein could not be produced.
Through a series of experiments testing animals' behavioral responses to temperature and other mechanical stimuli, they found that mice responded normally to hot, warm, and cold temperatures, but not to harmful cold.
GluK2 is primarily found in neurons in the brain, where it receives chemical signals and facilitates communication between neurons.
However, it is also expressed by sensory neurons in the peripheral nervous system (outside the brain and spinal cord).
“We found that this protein serves a completely different function in the peripheral nervous system, processing temperature cues instead of cold-sensing chemical signals,” said Dr. Bo Duan from the University of Michigan.
of GluK2 This gene has relatives across the evolutionary tree, going back to single-celled bacteria.
“Bacteria don't have brains, so why have they evolved a way to receive chemical signals from other neurons?” Professor Xu said.
“But the need to sense its environment, and perhaps both temperature and chemicals, will be very strong.”
“Thus, I suspect that temperature sensing is an ancient function, at least for some of these glutamate receptors, that was eventually adopted as organisms evolved more complex nervous systems. .”
of result appear in the diary natural neuroscience.
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W. Kai other. The kainate receptor GluK2 mediates cold sensing in mice. nut neurosi, published online on March 11, 2024. doi: 10.1038/s41593-024-01585-8
Source: www.sci.news
