Detection of somatostatin in the wild-type mammalian cochlea. A, B, somatostatin (red) cannot be detected in the cochlea of WT animals, although there is positive somatostatin staining on the tectorial membrane (B, TM); cell nuclei (DAPI) are in blue, and calbindin staining is in green. C, D, somatostatin-positive staining (red) is evident in the cortex and hypothalamus of WT mouse brain. E, Western blotting reveals that somatostatin can only be detected in protein extracts from brain tissue (positive control) but not in extracts from the OC, SV or SG. Actin serves as a standard to demonstrate that equal amounts of proteins have been loaded. Images by immunofluorescence microscopy; scale bar = 50 μm (A, C) or 25 μm (B, D).