Localization and distribution of PICK1 immunoreactivity in the dorsal root ganglion (DRG). A, Distribution of PICK1 immunoreactivity in the DRG cells of wild-type (WT; left) and PICK1 knockout (KO, right) mice. No immunoreactivity for PICK1 was observed in the DRG of PICK1 KO mice. Scale bar: 200 μm. B, Histogram showing the frequency of PICK1-positive and -negative somata in the DRG of WT mice by cross-sectional area.