Britannica Sources used in this answer

Why can some thermoreceptors respond to both temperature changes and chemicals?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

thermoreception in polar bears — Thermoreception Warm-blooded animals, such as polar bears, maintain stable body temperatures and adapt to substantial geographic and seasonal temperature fluctuations. Thermal adaptation is supported by the function of sensory structures called thermoreceptors.

Some thermoreceptors respond to both temperature changes and chemicals because they utilize transient receptor potential (TRP) channels, a superfamily of ion channels found in cell membranes. These channels function as molecular sensors that can be activated by specific thermal stimuli as well as by certain chemical compounds.12

For example, the receptor TRPV1 is activated by heat but also binds to capsaicin, the pungent component in red peppers, which triggers a burning sensation similar to that of high heat. Similarly, other receptors may respond to cooling stimuli and chemicals like menthol. Because these channels are polymodal, they allow a single receptor to detect diverse stimuli that initiate similar physiological or sensory responses. This molecular mechanism explains why certain substances can mimic the sensation of temperature changes.23