POTASSIUM AND CHLORIDE CHANNELS IN FRESHLY ISOLATED RAT ODONTOBLASTS

It has been suggested that understanding the physiological properties of odontoblasts may be important in understanding the mechanisms under lying both metabolic and transductive processes in dental pulp. Becaus e ion flux(es) may play a critical role in these events, it is of part icular interest to understand ionic mechanisms in odontoblast cells. T hus, the aim of this study was to use patch-clamp recording techniques to examine the properties of resident ion channels in freshly dissoci ated odontoblasts. In recordings made in potassium-rich solutions, cel ls displayed at least three distinct channel amplitudes, with conducta nces of 130 +/- 18 pS, 52 +/- 4 pS, and 25 +/- 2 pS, respectively. Cha nnel activity persisted in the presence of potassium salts of impermea nt anions, and could be abolished by barium, a non-specific potassium channel blocker. In addition to the potassium conductances, we saw two separate anion channels in the odontoblast membrane. These channels w ere predominantly chloride-selective, weakly permeable to both acetate and aspartate, and had conductances of 391 +/- 64 pS and 24 +/- 3 pS. While questions remain regarding the functional role of these and oth er ion channels that presumably reside in the odontoblast membrane, ou r results demonstrate that it is possible to study ionic mechanisms of the odontoblast at the level of the single cell.