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. 2009 Apr;156(8):1185–1195. doi: 10.1111/j.1476-5381.2009.00111.x

Figure 9.

Figure 9

Kv7/M-channels in the axon initial segment control action potential (AP) threshold in hippocampal CA1 pyramidal neurons: inclusion of ankyrin-binding peptide (ABP; see Figure 8) in the patch-pipette progressively reduces AP threshold. (A) Superimposed examples of single APs 5 (black trace) and 25 min (blue trace) post patching with ABP in the patch-pipette solution. Each AP was generated by a 5 ms depolarizing current injection from −70 mV, as shown in the schematic. The magnitude of the current injection was adjusted to ensure that the step produced only a single AP. The APs are also shown on an enhanced time scale below. Note that subsequent bath addition of XE991 (red trace) did not further reduce the AP threshold. (B) Average (blue squares) AP thresholds at the beginning and 25 min post patching with ABP in the internal pipette solution. Open black squares represent the effects in individual neurons. (C) Time course of the reduction in AP threshold with ABP. (From Shah et al., 2008).