By Karen Hopkin
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Sick of feeling chilly? Well, there may be a solution. Because researchers have generated genetically engineered mice that can't feel the cold. Their work is in the Journal of Neuroscience. [Wendy M. Knowlon et al., A Sensory-Labeled Line for Cold: TRPM8-Expressing Sensory Neurons Define the Cellular Basis for Cold, Cold Pain, and Cooling-Mediated Analgesia]
All mammals, us included, sense temperature and touch through nerve cells in the skin. On these nerve cells are different types of receptors that respond either to mechanical pressure in the case of touch, or to heat or cold.
Researchers were able to stop the production of the receptors for cold in the mice, while leaving the receptors for the other sensations intact. They put the cold-insensitive and normal mice in a box where the temperature of the floor ranged from a freezing 32 degrees Fahrenheit to a toasty 122. And they found that the normal mice avoided both extremes, while mice without cold receptors shied away from the hot plate but had no qualms about the chill.
Of course, the researchers were not trying to create comfy cold mice. The real intent was to see if it's possible to stop just one skin sensation. The hope is to design drugs that can dull pain without leaving patients numb. And thus to provide not-cold comfort.