How many times have you been shivering on a winter day, and wished that you were capable of simply not feeling the cold? Well, that’s just what scientists at the University of Southern California have done to a group of lab mice – they disabled the animals’ ability to sense cold, while leaving their ability to sense heat and touch intact. It is hoped that the research could lead to more effective pain medications for humans.
The research team, led by associate professor of neurobiology David McKemy, isolated and removed neurons in the mice that express a protein known as TRPM8. This protein is what relays the sensation of cold from the skin.
Those mice were then tested alongside a control group (which still retained their TRPM8 neurons), on a surface where the temperature ranged from 0 to 50ºC (32 to 112ºF). Members of the control group mostly stayed in an area with a temperature of about 30ºC (86ºF), avoiding both hot and cold extremes. The altered mice also avoided the overly-hot areas, but readily wandered into the coldest regions, even when the surface temperature was cold enough to be painful or dangerous.
In other tests that involved the animals’ sense of touch, such as one in which they had to balance on a rotating rod, there was no difference between the two groups.
McKemy and his team are hoping that their findings will help in the development of pain relievers that only affect the pain sensation itself – many existing medications, by contrast, simply leave the patient entirely numb.
A paper on the research was recently published in The Journal of Neuroscience.