Serotonergic control of excitability : from neuron to networks

Abstract

It has been known for several years that serotonin (5-hydroxytryptamine, 5-HT) acts on neuronal cell excitability in various complex organisms of the animal kingdom including humans. 5-HT stimulates a variety of 5-HT receptors which can transiently and locally alter the ion conductance in neurons, ultimately leading to change the activity of the whole neurobiological network. We have summarized here some evidence showing that 5-HT through its multiple 5-HT receptor subtypes controls the excitability of various neuronal cell populations in numerous ways. These controls evolve under various circumstances. The 5-HT modulation of excitability is more complex when we consider network level, and we have explored the meaning of this unclear notion in term of mechanisms in different organisms. Finally, we describe the 5-HT control of epilepsy which represents the extreme neuronal excitability disturbance.