King's College London

The molecular mechanisms underlying the distinct sensations of warmth and heat have remained unclear until recently. In 2016 we showed that the TRPM2 ion channel mediates the sensation of warmth in vivo1, while in 2018 Vandewauw et al2 found that three channels, TRPV1, TRPM3 and TRPA1, jointly mediate the sensation of painful heat. In one important respect, though, these papers disagreed: we found that TRPM2 contributed to the thermal response of isolated somatosensory neurons1,3, while Vandewauw et al proposed that TRPA1, and not TRPM2, was the only thermally-activated ion channel in somatosensory neurons apart from TRPV1 and TRPM32. In the work presented here we sought to resolve the roles of TRPM2 and TRPA1 in the thermal responses of sensory neurons.