WASHINGTON: In a study that resolves an issue that had left scientists in a bit of a deep freeze, researchers have identified the mechanism used by the body to sense cold temperatures.

Writing on Wednesday in the journal Nature, the researchers said they had pinpointed in mice a receptor in sensory nerve cells that plays the leading role in cold sensation.

This receptor and others involve in sensing temperatures offer potential targets for developing pain-relieving drugs, said David Julius, a University of California San Francisco physiology professor who worked on the study. "I think it's quite likely that these results translate to other mammals, including us," Julius said in a telephone interview.

Knowledge of the cold-sensing role of "menthol receptor TRPM8" could have medical implications such as improving the treatment of certain types of chronic pain, he said.

The identity of the receptor for cold sensation had eluded researchers in the field of sensory physiology. The TRPM8 receptor had been seen as a strong, albeit unconfirmed, possibility.

Such a receptor sitting on the surface of a sensory nerve fibre can be activated by certain stimulation like hot or cold, leading to a signal sent through the spinal cord to the brain. This enables the body to recognise a certain sensation.

The researchers found in 2002 that this receptor was activated when exposed to chemical cooling agents like menthol, a natural product of mint, and to cool air.

In this study, they confirmed the role of this receptor by creating mice without the gene that controls it. The mice were unable to discriminate between warm and cold until temperatures were lowered to extremes, the study found. "Less has been known historically about how we detect cold compared to heat," Julius said.