Fig. 3.

The protein expression pattern of P2Y₁, P2Y₂, P2Y₄, P2Y₆, and P2Y₁₂ receptors in the rat cochlea prior to the onset of hearing. a P2Y₁ immunolabeling at P8 was detected extensively in the cochlear partition, including Reissner's membrane, spiral limbus and spiral ligament, basal cells of the stria vascularis. P2Y₁ was also found in the hair cells in the organ of Corti. b P2Y₂ labeling at P6 was observed in the pillar cells and Deiters’ cells in the organ of Corti, the interdental cells and fibrocytes of the spiral limbus, the epithelial cells of the spiral prominence, and a small subgroup of spiral ganglion neurons. Furthermore, the arrowheads point at the expression at the insertion points of Reissner's membrane into stria vascularis and spiral limbus. Inset shows P2Y₂ expression in the interdental cells of the spiral limbus. c P2Y₄ receptor expression at P6 rat cochlea was distributed in the hair cells in the organ of Corti, Reissner's membrane, stria vascularis, and the spiral ganglion neurons. d P2Y₆ receptor protein expression in the P8 cochlea was detected in the cuticular plates of the hair cells in the organ of Corti and in the basal cells of the stria vascularis at a high level, but the expression in the Reissner's membrane epithelial cells and the interdental cell in the spiral limbus was weak. e P2Y₁₂ immunolabeling was established at P12, and its expression was limited to the head plates of pillar cells in the organ of Corti, dispersed expression in Reissner's membrane epithelial and mesenchymal cells, and the perinuclear region of spiral ganglion neurons. f Negative control, omitting the primary antibody, at P6 cochlea. Scale bar 50 µm; inset ofb: 10 µm. bc basal cells, is inner sulcus, o/C organ of Corti, os outer sulcus, rm Reissner's membrane, sb spiral limbus, sgn spiral ganglion neurons, sl spiral ligament, sv stria vascularis