FIG. 1.

Concentration of sodium channels and fibroblast growth factor homologous factor (FHF) at the axon initial segment of P20 granule cells. Saggital cryosections of P20 cerebellum were incubated with mouse monoclonal antibody to voltage-gated sodium channel alpha subunits (A) or to FHF-4 monoclonal antibody (B), followed by treatment with goat anti-mouse IgG-ALEXA488 and with TO-PRO3 as a nuclear stain. Confocal images were captured at ×4,000 magnification. An individual granule cell nucleus (]) and its axon initial segment (▴) are indicated for each image.