Figure 1.

Ion channel localization with ankyrin-G. A, B, Ankyrin-G aligned at the HP in the apical cochlea by P7 and in the basal turn by P6 as nodes developed (arrowheads). C, Pan-Na_V1 colocalized with ankyrin-G and Na_V1.6 near the HP. D, K_V3.1b colocalized with ankyrin-G and Na_V1.6. E, View of HP and distal OSL with enlargements in grayscale for heminodes at the HP (top row) and nodes in the OSL (bottom rows). F, M₁ and M₂ (top and bottom, respectively, see Materials and Methods) versus postnatal day for heminodes (left) and nodes (right) illustrate the development of colocalization. ROIs (n = 20–210 per data point) were determined by outlining regions near the HP (∼70 μm²) or OSL (∼4 μm²). SEM ranged from 0.00 to 0.03 (data not shown). Spatial overlap with ankyrin-G increased over development for Pan-Na_V1, Na_V1.6, and K_V3.1b; M_{2, P30} > M_{2, P11}, p < 10⁻⁴, Student's two-tailed t test. G, At heminodes, Na_V1.1 partially overlapped Na_V1.6 and ankyrin-G. H, K_V2.2 expression extended from juxtaparanodes centrally. I–K, K_V7.2 and K_V7.3 expression in the OSL, at the HP, and in the ISP under IHCs. J, Calretinin-labeled IHCs. K, Na⁺/K⁺-ATPase-labeled ANF membranes. Scale bars, 10 μm.