Amiloride-sensitive sodium currents in identified taste cells of the frog

Sodium ions occurring in food are thought to be detected, at least in part, through specific amiloride-sensitive, sodium channels (ASSCs) localized in taste receptor cells. Cells within taste buds are morphologically heteroge neous, and include taste receptor cells and other cells that could perform a support or even transduction role. It is not known whether subsets of the taste bud cells express ASSCs, and whether the properties of these channel s are similar. By applying the patch-clamp technique to morphologically dis tinct cells, the supporting wing cells, isolated from the frog taste disk, I have found functional ASSCs that are moderately sensitive to amiloride (K i 3-4 muM) and which are distinctly lower in affinity for amiloride than re ported frog taste receptor cells (K-i 0.2 muM). These results support the h ypotheses of the existence of distinct, functional ASSCs in different cell morphotypes, at least in frog taste organs. Neuro Report 12:1315-1321 (C) 2 001 Lippincott Williams & Wilkins.