Immunolabelling for Kir4.1 (A–C) and GLAST (D&E).

<p><b>A,B Kir 4.1 in undamaged organ of Corti. </b><b>A.</b> Whole mount preparation. Labelling for actin (green) shows the hair cells. Kir 4.1 (red) is present in the Deiters' cell bodies and is strongly expressed in the “cup” region that encloses the base of an OHC (arrows), but there is no labelling in the phalangeal processes (e.g. in the gap between the bodies of OHC2 and OHC3). Kir4.1 is also strongly expressed in the plasma membranes of the supporting cells around the IHC. <b>B.</b> Frozen section. The stria vascularis (SV) shows intense labelling (of intermediate cells) with equally intense labelling in the supporting cells of organ of Corti (OC) – shown at higher power in the inset. (Hair cells immunolabelled for myosin 7a (green); green arrow indicates OHC). <b>C. Kir 4.1 in repaired organ of Corti at 2 weeks post-treatment, C57BL/6 mouse.</b> With loss of OHC, there is significantly reduced immunolabelling for Kir4.1 in the organ of Corti (OC), shown at higher power in the inset, (arrows indicate actin labelling of the reticular lamina), but Kir4.1 is still strongly expressed in the stria vascularis (sv). <b>DD'. GLAST in undamaged organ of Corti.</b> D. GLAST is strongly expressed by supporting cells around the IHC (immunolabelled for calretinin) but is absent from the phalangeal processes of Deiters' cells. D' Confocal optical sectioning at a deeper level shows GLAST labelling at the membranes of the bodies of Deiters' cells (arrow). <b>EE'. GLAST in repaired organ of Corti in C57BL/6 mouse; 4 weeks post-treatment.</b> Focus at the plane of the reticular lamina (E) shows the characteristic pattern actin labelling (blue) of cell junctions between Deiters' cells in the repaired epithelium after loss of OHC. GLAST is still strongly expressed by inner phalangeal and inner border cells although IHC have also been lost. Focus at a deeper level (E') reveals labelling for GLAST in the plasma membranes of the Deiters' cells (arrow) delineating their shapes, which show similar irregularities to that revealed by labelling for KCC4 in the repaired epithelium. Scale bars: 10 µm in all panels.