In the normal cochlea, the copper transporter Ctr1 and copper pumps ATP7A and ATP7B were localized in the organ of Corti (A-C), epithelium of the stria vascularis (D-F), and the spiral ganglion neurons (G-I). Representative confocal photomicrographs of neonatal rat cochlear organotypic cultures show immunolabeled (green) Ctr1 (A, D and G), ATP7A (B, E and H) and ATP7B (C, F and I). (A-C) Vertical plane images provide a surface view of the organ of Corti; Ctr1 (A) and ATP7B (C) were localized in the outer hair cells (OHC), whereas ATP7A (B) showed extensive labeling in the pillar cells (PC). (D-F) The marginal (MC), intermediate (IC) and basilar (BC) cell layers of the stria vascularis are shown in cross-section. (G-I) Note that yellow-labeled spiral ganglion neurons (SGN) are the result of overlap of green and red labeling. Scale bars shown in panels A, D, and G each represent 10 μm.