In this video, I discuss the neurotransmitter serotonin. I cover serotonin synthesis, the primary location of serotonin-producing neurons, serotonin receptors, and functions of serotonin.

TRANSCRIPT:

Welcome to 2 minute neuroscience, where I explain neuroscience topics in 2 minutes or less. 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 raphe nuclei. 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 unclear 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.

Reference:

Nichols DE, Nichols CD. Serotonin Receptors. Chem Rev. 2008, 108: 1614-1641.

Caption author (Arabic) Shwan Hameed