Ionic currents underlying the generation of the action potential

It generates thanks to the sudden activation of voltage-gated sodium channels that mediate a sub-millisecond sodium current responsible for the rising phase of the spike. Using a combination of ultrafast imaging techniques and a novel peptide selective for the sodium channel subtype Nav1.2, a LIPhy group analysed the action potential generation in the axon of cortical pyramidal neurons of the mouse [*]. They found that the sodium channel Nav1.2 also carries a calcium current that activates the BK potassium channel determining the shape of the action potential. This finding advances our knowledge of the action potential generation and it can be also important for the understanding of several neuronal disorders associated with membrane excitability.

Reference :

[*] Filipis L, Blömer LA, Montnach J, Loussouarn G, De Waard M, Canepari M. Nav1.2 and BK channel interaction shapes the action potential in the axon initial segment. J Physiol. 2023 Mar 22. doi: 10.1113/JP283801.