Fig. 6. Early aspect of nodal and paranodal regions in wild-type and jimpy mice. Sections from corpus callosum of wild-type (A) or jimpy (B) littermates, were examined by double immunostaining with antibodies against paranodin (green) and Na⁺ channels (red) at postnatal day 8. In wild-type mice, paranodin immunoreactivity was concentrated in binary or single paranodes, flanking the nodal cluster of Na⁺ channels. In many instances, Na⁺ channels clusters were observed independently from paranodes (arrows in A). In jimpy, paranodin was distributed irregularly, without bona fide identifiable paranodal labeling, whereas the clusters of Na⁺ channels appeared essentially normal and comparable with those in wild-type littermates. Scale bar: 20 µm.