USC scientists turn off the ability to feel cold
By Robert Perkins
14 February 2013
USC neuroscientists have isolated chills at a cellular level, identifying the sensory network of neurons in the skin that relays the sensation of cold.
David McKemy, associate professor of neurobiology at the University of Southern California's Dornsife College of Letters, Arts and Sciences, and his team managed to selectively shut off the ability to sense cold in mice while still leaving them able to sense heat and touch.
In prior work, McKemy discovered a link between the experience of cold and a protein known as TRPM8 (pronounced trip-em-ate), which is a sensor of cold temperatures in neurons in the skin, as well as a receptor for menthol, the cooling component of mint.
Now, in a paper that appears in The Journal of Neuroscience on 13 February, McKemy and his co-investigators have isolated and ablated the neurons that express TRPM8, giving them the ability to test the function of these cells specifically.
Using a mouse-tracking software program developed by one of McKemy's students, the researchers tested control mice and mice without TRPM8 neurons on a multi-temperature surface. The surface temperature ranged from 0 degrees to 50 degrees Celsius (32 to 122 degrees Farenheit), and mice were allowed to move freely among the regions.
The researchers found that mice depleted of TRPM8 neurons could not feel cold but still responded to heat. Control mice tended to stick to an area around 30 degrees Celsius (86 degrees Fahrenheit) and avoided both colder and hotter areas. But mice without TRPM8 neurons avoided only hotter plates and not cold - even when the cold should have been painful or was potentially dangerous.