Baby, it’s Cold Outside!

How do you know that it’s chilly?

A short explanation of TRP proteins.

As Valentine’s day approaches a polar vortex is descending from Canada on the contiguous US and frigid temperatures are expected across much of the nation. The sensation of cold is perceived by protein channels in the skin. There are a number of these protein channels and they each have a different temperature range they respond to. The proteins are collectively referred to as Transient Receptor Potential (TRP) channels.

A common temperature receptor protein in skin is the TRPM8 channel and it is a receptor that provides a response to cool temperatures. These temperature receptors are also chemical sensors and can be activated by compounds applied to the skin. The TRPM8 receptor is strongly activated by menthol and eucalyptol, both of which mimic the cooling sensation that a temperature change elicits with this protein. Other terpenoids that also activate this protein, but do not elicit a cooling sensation are hydroxy citronellal, geraniol, and linalool.

Activation is not a binary process but can elicit a graduated response which drives different physiological responses which may include complex behaviors like shivering when cold. These proteins are important in many species and it has been recently reported that pandas will roll in manure to desensitize themselves to the extreme cold. They are utilizing terpenes in the manure to desensitize these proteins in a manner similar to applying icy-hot to the skin to reduce pain after a workout.

An advantage we have is that we can dress more warmly in response to the cold so this weekend, remember to wear a hat and mittens. In future posts, we will consider other TRP channels and how they respond to stimulation.

Dr. Randal Stahl – Science Consultant