In situ hybridization analysis of α, β and γ ENaC subunits in vallate (A-C), foliate (E-G) and fungiform (I-K) papillae of control rats. In each row, the sequence is α, β, γ from left to right. D and H are positive (α gustducin mRNA) and negative (using sense probe) controls on circumvallate papillae, respectively. Outlines of taste buds are shown by dotted lines. Arrows indicate stained cells within taste buds and arrowheads indicate those outside of taste buds. Higher magnification of α ENaC subunit in vallate and foliate taste buds is indicated in A and E, respectively. Scale bars are 50 μm for A-H and 25 μm for I-K.