Cold pain converts into burning pain – thermosensitivity of menthol activated C nociceptors

Introduction: Cold hyperalgesia is an important, but poorly understood symptom in neuropathic pain. A new model for cold pain showed that menthol acts to sensitize cold sensitive peripheral C nociceptors and activates cold specific A delta fibers by a cold channel (TRPM8). It is unclear at which environmental temperatures cold specific C nociceptors are activated by menthol. Methods: In 11 subjects menthol was topically applied to the forearm during local warming (39°C) and cooling (13°C). The skin was warmed and cooled, respectively, 5min prior to menthol and the skin temperature was kept constant during the 15…