Welcome to 2 minute neuroscience, where I explain neuroscience topics in 2 minutes or
In this installment I will discuss serotonin.
Serotonin is a monoamine neurotransmitter, a term that refers to its chemical structure
and the fact that it is derived from an amino acid.
To synthesize serotonin, the amino acid tryptophan is converted to 5-hydroxytryptophan, or 5-HTP,
and 5-HTP is converted to serotonin, or 5-HT.
Serotonin neurons are primarily found in the brainstem in clusters of neurons called the
Serotonin neurons from the raphe nuclei project throughout the brainstem and brain, and provide
serotonin to the rest of the central nervous system.
Researchers have identified 7 different families of serotonin receptors, which differ from
one another in distribution, the substances that bind to them, and the effects they mediate.
All but one of these families of receptors consists of G-protein coupled receptors, the
other receptor family consists of ligand-gated ion channels.
Within these 7 families of receptors, 14 receptor subtypes have been identified as well.
Serotonin is removed from the synaptic cleft by a transport protein called the serotonin
transporter, or SERT.
In terms of function, serotonin is often linked to mood in part due to the understanding that
many antidepressants cause serotonin levels to rise.
However, an attempt to define any neurotransmitter by one function is inevitably an oversimplification.
In truth, serotonin’s role in mood is very complex and depression is not likely to be
due to a simple serotonin deficiency.
Additionally, serotonin is involved in a long list of functions other than mood.
In most cases its actual role in those functions is still not completely understood.