Figure 2.

Purkinje cells and synaptophysin-immunoreactive puncta at various ages (calbindin and synaptophysin immunocytochemistry and DAPI counterstaining).

Calbindin-immunoreactive Purkinje cells (red), synaptophysin-immunoreactive presynaptic puncta (green), and DAPI-labeled nuclei (blue) were visualized. At P3, Purkinje cells in the PCL (red) had short processes. The dendrites did not extend into the molecular layer. (A) Synaptophysin-immunoreactive puncta (green) were located around Purkinje cells. At this age, there were almost no synaptophysin-immunoreactive puncta in the molecular layer. (B) At P7, many dendrites extended into the molecular layer, and there was a large increase in the number of synaptophysin-immunoreactive presynaptic puncta around cell bodies, dendrites and spines. At P30, the branched dendrites of Purkinje cells had filled the molecular layer, and the dendrites had reached the pia. (C) Synaptophysin-immunoreactive puncta were very dense around Purkinje cells. After P12M, the synapses showed signs of aging, and the number of synaptic buttons decreased. (D) At P18M, the number of synaptophysin-immunoreactive buttons was at a minimum. Scale bar: 20 μm. P3, P7, P30: Postnatal 3, 7, 30 days; P12M, P18M: postnatal 12, 18 months. ML: Molecular layer; PCL: Purkinje cell layer; IGL: internal granular layer.