American Pain Society's 27th Annual Scientific Meeting (May 8 – 10, 2008): Cooling-activated TRP Channels in Physiological and Pathological Cold Sensation

Ion channels of the Transient Receptor Potential family (TRP channels) have recently been identified as the molecular machinery that mediates the transduction of thermal stimuli into neuronal activity in the peripheral nervous system. Several TRP channel family members are activated by thermal stimuli, and the combined action of several thermo-TRPs (TRP channels activated by heating or cooling) covers the entire physiological range of temperatures. Thus, cooling activates TRPM8, warming activates TRPV3, and noxious heat activates TRPV1 and TRPV2 at higher temperatures. TRPA1 has also been suggested, with some controversy, as a detector of noxious cold stimuli. This symposium provides an introduction to cold-activated TRP channels, including basic mechanisms of channel gating as well as their role in both normal temperature sensation and in pathological conditions that result extreme hypersensitivity to cold. Dr. Voets will discuss basic mechanisms of activation of TRP channels by changes in temperature. Dr. Gu will then present data suggesting that upregulation of TRPM8 might be responsible for cold hypersensitivity in neuropathic pain conditions. Dr. Dhaka will then discuss studies of TRPM8 and TRPA1 knockout mice, describing the behavioral consequences of genetic removal of these ion channels. These presentations will be followed by a discussion period.