Axon Initial Segment

Dominique Debanne (1) , Juan José Garrido

1 UNIS - Inserm U1072 - Unité de Neurobiologie des canaux Ioniques et de la Synapse

The axon initial segment (AIS) is a specialised region of the axon where the action potential is initiated following integration of excitatory and inhibitory inputs. The AIS contains high density of sodium and potassium channels anchored on scaffold proteins, but it also includes receptors to neurotransmitters and neuromodulators. Besides its role in action potential initiation, the AIS constitutes a diffusion barrier that controls cytoplasmic traffic towards the axon. Activity-dependent plasticity has been recently shown to affect the length and position of the AIS whereas stimulation of ligand-gated receptors alters the ion channel content of the AIS. Thus, the AIS represents a critical element in neuronal excitability and its plasticity.

Keywords: Action potential; Ion channels; Neuron; Excitability; Plasticity

Domains: Life Sciences [q-bio]; Neurons and Cognition [q-bio.NC]; Life Sciences [q-bio]; Neurons and Cognition [q-bio.NC]; Neurobiology

Dominique Debanne, Juan José Garrido. Axon Initial Segment. Encyclopedia of Life Sciences, 2018, ⟨10.1002/9780470015902.a0000004⟩. ⟨hal-01963287⟩