Abstract
The axon is responsible for integrating synaptic signals, generating action potentials (APs), propagating those APs to downstream synapses and converting them into patterns of neurotransmitter vesicle release. This process is mediated by a rich assortment of voltage-gated ion channels whose function can be affected on short and long time scales by activity. Moreover, neuromodulators control the activity of these proteins through G-protein coupled receptor signaling cascades. Here, we review cellular mechanisms and signaling pathways involved in axonal ion channel modulation and examine how changes to ion channel function affect AP initiation, AP propagation, and the release of neurotransmitter. We then examine how these mechanisms could modulate synaptic function by focusing on three key features of synaptic information transmission: synaptic strength, synaptic variability, and short-term plasticity. Viewing these cellular mechanisms of neuromodulation from a functional perspective may assist in extending these findings to theories of neural circuit function and its neuromodulation.
Highlights
Neuromodulators exert powerful control over both neuronal circuit activity and animal behavior throughout the brain (Marder, 2012; Nadim and Bucher, 2014)
Neuromodulatory regulation of ion channels affects how ion channels respond to voltage deflections on short and long time scales, affecting how certain features of synaptic input are transformed into neuronal output
We focus primarily on studies performed in vertebrate central circuits, drawing from neuromodulatory systems like dopaminergic and GABAB receptor systems in which significant mechanistic detail has been elucidated
Summary
The axon is responsible for integrating synaptic signals, generating action potentials (APs), propagating those APs to downstream synapses and converting them into patterns of neurotransmitter vesicle release. This process is mediated by a rich assortment of voltage-gated ion channels whose function can be affected on short and long time scales by activity. We examine how these mechanisms could modulate synaptic function by focusing on three key features of synaptic information transmission: synaptic strength, synaptic variability, and short-term plasticity. Viewing these cellular mechanisms of neuromodulation from a functional perspective may assist in extending these findings to theories of neural circuit function and its neuromodulation
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have