DEG/ENaC ion channels involved in sensory transduction are modulated by cold temperature

Several DEG/ENaC cation channel subunits are expressed in the tongue and in cutaneous sensory neurons, where they are postulated to function as recept ors for salt and sour taste and for touch. Because these tissues are expose d to large temperature variations, we examined how temperature affects DEG/ ENaC channel function. We found that cold temperature markedly increased th e constitutively active Na+ currents generated by epithelial Na+ channels ( ENaC), Half-maximal stimulation occurred at 25 degreesC. Cold temperature d id not induce current from other DEG/ENaC family members (BNC1, ASIC, and D RASIC), However, when these channels were activated by acid, cold temperatu re potentiated the currents by slowing the rate of desensitization. Potenti ation was abolished by a "Deg" mutation that alters channel gating. Tempera ture changes in the physiologic range had prominent effects on current in c ells heterologously expressing acid-gated DEG/ENaC channels, as well as in dorsal root ganglion sensory neurons. The finding that cold temperature mod ulates DEG/ENaC channel function may provide a molecular explanation for th e widely recognized ability of temperature to modify taste sensation and me chanosensation.