Vicissidude writes "As an ice cream melts in your mouth this summer, take a moment to contemplate the protein that may be bringing you that sense of cool relief — and numbing your tongue. Researchers have pinned down the particular protein in mice used by the body to sense cold temperatures, and think that a similar one in humans does the same job. Mice rely on a single protein, called TRPM8, to sense both cold temperatures and menthol, the compound that gives mints their cool sensation. The sensor also controls the pain-relieving effect of cool temperatures, but does not seem to play an important role in the response to painfully cold temperatures below 10 C. TRPM8 is in the same family as the protein that detects heat and capsaicin, the compound that makes peppers hot. These proteins lie in the cell membranes of select neurons, and form channels that open and close in response to external signals."