Try putting an ice-cube in your mouth. The insides of your mouth and tongue instantly turn numb.
Hold it in still and you will feel pain. Now try sucking on peppermint. The mint itself is at room temperature, but your mouth instantly feels cold and numb. How did it do that?
The answer is menthol, the ingredient that instantly tricks your brain into sensing that the food is cold.
Nerves are the wiring of the brain, carrying information in the form of electric currents.
Our nervous system is built to sense changes in temperatures – a whole set of nerves running from our skin to the brain is dedicated to conveying just that information.
The receptor protein that senses the change in temperature is called TRPM8 and it is found in all cold-sensing nerve cells.
TRPM8 is a voltage gated ion-channel protein – meaning it allows entry of calcium ions on sensing change in temperature.
We don’t exactly understand how TRPM8 does it. Whenever there is a drop in temperature, the voltage on TRPM8 somehow changes and its shape changes so that it allows calcium ions to flow into the nerve cell.
This triggers current to flow from the membrane of the nerve cell. This current carrying vital information warns the brain of the temperature fall.
Peppermint drops fire up TRPM8 in cold-sensing nerves and make your mouth instantly feel cool.
Even after you have swallowed, some menthol remains and keeps the nerves activated. Just a sip of water can get the nerves fired up again.
Just like your mouth feels numb when you eat peppermint, applying menthol on your skin activates the cold-sensing nerves making the area go numb.
Read more.
