Voltage-gated potassium (Kv) channel distribution in the axon initial segments (AISs) in motor neurons (MNs). Triple immunostaining of Peripherin (A, F, K, P), ankyrin G (AnkG) (B, G, L, Q) and Kv channels: KCNQ2 (C), Kv1.1 (H, S), Kv1.2 (M) and Kvβ2 (R) (Kv and AnkG are merged in (D, I, N); Kv1.1 and Kvβ2 are merged in (T). (E, J, O) The mean immunofluorescence intensity profile (shown by the line) ± SEM from n = 6 AISs is shown for AnkG and Kv channels. For each AIS and each antibody, immunofluorescence intensities were normalized relative both to its maximum intensity along the AIS and to the length of the AIS. The beginning and the end of the AnkG+ AIS in (B, G, L, Q) are shown (also in E, J, O) by red arrowheads. Brackets indicate Kv channel expression domains. Scale bar = 5 μm.