Summary: Have you ever noticed how a cold breeze or a stick of mint gum produces an unmistakable cooling sensation? Scientists have now captured the first molecular “snapshots” of TRPM8, the main cold sensor in the body. Using cryo-electron microscopy, researchers imaged this protein channel as it shifts from closed to open, revealing how it detects true cold and how menthol produces a similar sensation by activating the same channel.
This work explains why menthol feels cold even at room temperature and provides a structural basis for developing new therapies for conditions linked to TRPM8 dysfunction, including chronic pain, migraines, and dry eye disease.
Key Facts
- The TRPM8 sensor: TRPM8 is a protein channel in sensory neurons of the skin, mouth, and eyes that opens in response to cool temperatures, triggering nerve signals between roughly 46°F and 82°F.
- How menthol works: Menthol binds to a different region of TRPM8 than cold does, but induces structural changes that open the same ion-conducting pore, producing a cooling sensation without a drop in temperature.
- Molecular snapshots: Researchers used cryo-electron microscopy to freeze TRPM8 in multiple states and image the conformational steps as the channel transitions from closed to open.
- The “cold spot”: A distinct region of the protein essential for temperature detection helps prevent the channel from becoming desensitized during prolonged cold exposure.
- Medical potential: Structural insight into TRPM8 opens new opportunities to design targeted drugs for migraine, chronic pain, dry eye, and other conditions linked to altered cold-sensing.
Source: Biophysical Society
When a winter morning air hits your face or you pop a mint into your mouth, TRPM8 springs into action, alerting your brain to cool sensations.
For the first time, scientists have visualized how this sensor works at the molecular level. The new images reveal how TRPM8 detects both actual cold and chemical coolness from compounds like menthol, explaining a long-standing mystery in sensory biology.
The results will be presented at the 70th Biophysical Society Annual Meeting in San Francisco, February 21–25, 2026.
The team focused on TRPM8, a membrane protein that functions like a microscopic thermometer inside sensory neurons. “It’s the primary sensor that tells your brain when it’s cold,” said Hyuk-Joon Lee, a postdoctoral fellow in Seok-Yong Lee’s lab at Duke University. Although scientists knew TRPM8 produced cold sensations, its structural mechanism was previously unclear; these new images reveal how the channel changes shape to allow ion flow and trigger nerve signals.
TRPM8 resides in neurons that innervate the skin, oral cavity, and eyes. At cool temperatures (approximately 46°F to 82°F), the channel opens and permits ions to enter the cell, initiating electrical signals that the brain interprets as cold. Compounds such as menthol and eucalyptus produce similar sensations by activating TRPM8.
Menthol acts like a molecular trick: it binds to a site distinct from the cold-sensing region and induces conformational changes that propagate to the pore, opening the channel. In effect, menthol causes the same neuronal response as true cold, which is why it feels chilly despite no temperature change.
Using cryo-electron microscopy, the researchers flash-froze TRPM8 samples and captured multiple conformational states. They found that cold and menthol activate TRPM8 via overlapping yet distinct allosteric pathways: cold primarily alters the pore region directly, while menthol binds elsewhere and transmits a shape change to the pore. When cold and menthol are combined, their effects amplify each other, allowing the team to capture the channel in a stable open conformation that had been difficult to observe with cold alone.
These structural insights have practical implications. Malfunctions in TRPM8 signaling have been associated with migraines, chronic pain, dry eye, and certain cancers. One therapeutic example is acoltrimon, an FDA-approved eye drop that activates TRPM8; as a menthol analogue, it stimulates the cooling pathway to increase tear production and relieve ocular irritation. A detailed molecular map of TRPM8 will help researchers design more selective drugs to modulate this channel for therapeutic benefit.
The team also pinpointed a “cold spot,” a portion of the protein critical for sensing temperature and preventing desensitization during long exposures to cold. Identifying this region clarifies how TRPM8 integrates temperature and chemical signals to produce the perception of coolness, answering a basic question about sensory transduction.
Key Questions Answered:
A: Menthol binds to TRPM8 and forces the channel into an open state. That opening sends the same neural signal to the brain as actual cold, so you perceive a cooling sensation without an actual drop in temperature.
A: Potentially yes. TRPM8 contributes to how the nervous system processes certain pain signals. Structural knowledge of the channel enables rational drug design to modify its activity and reduce pain signaling in conditions like migraine.
A: Cryo-electron microscopy is a method that flash-freezes proteins and images them with an electron beam, allowing researchers to capture high-resolution structures of molecules in different functional states.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by editorial staff.
About this neuroscience and pain research news
Author: Leann Fox
Source: Biophysical Society
Contact: Leann Fox – Biophysical Society
Image: The image is credited to Neuroscience News
Original Research: Findings to be presented at the 70th Biophysical Society Annual Meeting