Fig. 5. Localization of Na⁺ and K⁺ channels in jimpy mice. Sections from corpus callosum of wild-type (A,C) or jimpy (B,D) littermates were examined by double immunostaining with antibodies against the Na⁺ channels (green) and the K⁺ channels Kv1.1 (red). Postnatal day 15 (A,B). In wild-type mice, Kv1.1 immunoreactivity was clearly separated from Na⁺ channels clusters by an empty space corresponding to paranodes (A). In jimpy mice, although the shape of Na⁺ and K⁺ channel clusters was roughly comparable with that in wild-type littermates, the localization of Kv1.1 immunoreactivity was abnormal as it was not separated from the nodal Na⁺ channels (arrowhead, B). Postnatal day 21 (C,D). The alteration of K⁺ channels distribution was much more severe than at P15. Immunoreactivity appeared more diffuse, and Kv1.1 aggregates were irregular and fragmented. The shape of Na⁺ channels clusters was also altered with fuzzy and irregular limits. Scale bar: 10 µm.