a) The proportion of β-galactosidase positive type II (PLCβ2 and α-gustducin) and type III (NCAM) taste cells is significantly reduced in circumvallate taste buds of older mice (black bars: 10 week-old; white bars: 25 week-old mice). b) In fungiform taste buds, a similar trend of fewer β-galactosidase immunoreactive type II and III taste cells is evident, but this shift is not significant. Examples of taste buds from 25 week-old with limited β-galactosidase expressing type II (c,d,f,g) and type III (e,h) cells in 0.75 µm optical sections from circumvallate (c,d,e) and fungiform (f,g,h) papillae. Student’s t-test, n = 3 mice. *, p<0.05; **, p<0.01. Scale bars = 10 µm in all panels.