Fig. 6.

PSD-95 staining of cochlear whole mounts. A, C Abnormal terminals in the IHC area of ouabain-treated ears are far from synaptic puncta. IHC area from a control ear (A) and a ouabain-treated ear 1 week posttreatment (C), viewed as y-z projections. In the control ear, synaptic ribbons (anti-CtBP2: red) are almost always juxtaposed to postsynaptic densities (PSD-95: green): one is shown at the red-green arrow. In the ouabain-treated ear (C), there are orphan ribbons (red arrow), and orphan PSD-95 patches (green arrow), and the ectopic terminals (white arrows) are sometimes near ribbons, but never near synapses. B, D Ouabain has minimal effect on the synaptic architecture in the OHC area: OHC area from the same control and ouabain-treated ears shown in A and C, respectively. The small number of PSD-95 patches is confined to very basal pole of the OHCs (red-green arrows). All image stacks are maximum projections from the 8 kHz region. Each was acquired as a z-stack through ∼10 adjacent IHCs, with the x–y focal plane parallel to the basilar membrane, and then reprojected to the y–z plane to mimic a radial-section view. In each panel, the approximate outlines of hair cell basolateral membranes (and nuclei) are indicated by the dashed yellow lines. Scale bar in A applies to all panels.