Figure 3.

Distribution of K ⁺ channels in the CNS. Sections of optic nerve from wild-type (A, C, E, G, I, and K) or Caspr2-null mice (B, D, F, H, J, and L) were double labeled with antibodies to Caspr (C, D, I, and J) and Kvβ2 (G and H), or Kv1.2 (A and B). Merge images are shown in panels E, F, K, and L. The images were obtained under the same exposure conditions. Note the decrease in K⁺ channels staining in Caspr2−/− nerves. Inset in L shows measurements of the fluorescence intensity labeling of K⁺ channels in Caspr2-null compared with wild-type nerves in integrated optical density units. Three images at 40× were used for each genotype, and errors are given as ± SEM. Inset in F shows the levels of Kv1.2 protein detected by immunoblots in sciatic nerve lysates from wild-type (+/+) or Caspr2-null (−/−) mice. Bar, 20 μm.