Figure 3. Expedited morphological development of Purkinje cells in 5-HT_3A receptor knockout mice.

A, Purkinje cells from P8 mice show the following four stages of morphological maturation: stage I is the most immature stage, in which Purkinje cells have multiple primary dendrites in all directions; stage II is a stage in which Purkinje cells still have multiple primary dendrites, but which are already polarized into one direction; stage III are Purkinje cells which have one primary dendrite with a very immature dendritic tree; and stage IV is the last stage before the final maturation, in which Purkinje cells have one primary dendrite with an almost fully developed dendritic tree. B, distribution of Purkinje cells in each morphological maturation stage in both WT and 5-HT_3A receptor knockout mice at P7, P8 and P9 shows that Purkinje cells from 5-HT_3A receptor knockout mice display a more mature morphology at an earlier age than Purkinje cells from WT mice. The numbers underneath the bars of the graphs indicate the number of cells used for analysis.