(A) In wild-type mice, the number of fungiform papillae increased from E13.5 to E15.5. The number was almost equal from E15.5 to P0. In BDNF−/−xNT-3−/− mice, the number increased from E13.5 to E15.5 even though that number was always less than in wild-type mice. However, the number decreased from E15.5 to E17.5, and the reduction was significant between E15.5 and P0. (B) Relative size of the circumvallate papilla in wild-type and BDNF−/−xNT-4−/− mice from E13.5 to P0. At E13.5, there is no difference. But from E15.5 to P0, the size in wild-type mice was significantly larger than in BDNF−/−xNT-3−/− mice. (A, B) Error bars represent standard deviation. Asterisks (*, **) represent significance levels (P<0.01).