Figure 2.

The cochlea expresses an HPA-equivalent signaling system. Immunofluorescent labeling of POMC, ACTH, and MC2R reveals expression of classic HPA components in the cochlea. A, D, G, POMC and ACTH are expressed in inner and outer sulcus cells lining the cochlear duct (IS and OS, respectively). MC2 is expressed in these regions to a lesser extent (C). All components are expressed in the spiral ganglion cells (SG). The organ of Corti region is boxed in A and is the region from which the higher magnification illustrations were produced. B, C, Higher magnification of the organ of Corti region reveals intense POMC labeling in the Deiters' cells (DCs) (B), and this expression overlaps with CRFR1-GFP label (C). E, F, ACTH shows less immunolabeling in Deiters' cells compared with POMC, but an intense labeling of the IHC. H, I, Finally, in the organ of Corti region, MC2R shows an intense and specific labeling for the IHC and a lack of Deiters' cell labeling. Scale bars: A (for A, D, G), 60 μm; B (for B, C, E, F, H, I), 10 μm. HC, Hensen's cell. CRFR1 designates CRFR1-GFP immunolabeling.