Enrichment of tetraploidy in calbindin-positive neurons in the mouse striatum. A, Cells isolated from the striatum of adult mice immunostained with an anti-calbindin-specific antibody and counterstained with DAPI. Arrow, A calbindin-positive neuron. B, Neurons immunostained with the anti-calbindin antibody, isolated from the cerebral cortex (Cortex) or striatum (Striatum) from P0 mice, were stained with PI and subjected to flow cytometry. The percentage of calbindin-positive neurons in the 4C population is shown for each tissue. ***p < 0.005 (Student's t test). Scale bar, 10 μm.