Serotonin belongs to a wider category of neurotransmitters known as monoamines. More specifically, it is called an endolamine. These names describe serotoninís chemical properties. Another name for serotonin is 5-hydroxytryptamine (5-HT), which scientists prefer mainly because it describes the chemical makeup of the neuron.
Although serotonin is a very important neurotransmitter, only a small percentage of the bodyís serotonin (1-2 %) is found in the brain. Since the brains serotonin levels are studied in relation to MDMA, the description here will apply to the serotonin found in the brain. The connection between serotonin activity and hallucinogenic drugs began when researchers discovered that LSD mainly affects serotonin in the brain. It was also observed that the effects of LSD and aspects of MDMA are similar. Thus, researchers thought that the hallucinogenic effects of MDMA are caused by its interactions with serotonin systems in the brain.
Serotonin synthesis begins with the
tryptophan. The next step in serotonin production involves an
enzyme named tryptophan hydroxylase. Tryptophan hydroxylase adds a
hydroxyl group to tryptophan, creating 5-hydroxytryptophan. Another enzyme, amino acid decarboxylase, removes a
carboxyl group from 5-hydroxytryptophan, leaving 5-hydroxytryptamine, or serotonin.
The neurons in the brain that release serotonin all originate in small, dense collections of neurons called Raphe Nuclei. The Raphe Nuclei are located in the medulla, pons, and midbrain, which are located at the top of the spinal cord. Serotonergic neurons have axons which project to many different areas in the brain; therefore serotonin affects many different behaviors.
Research thus far has shown that serotonin is mainly involved in mood regulation; control of basic activities such as eating, sleep and arousal; and control of pain. Serotonin also plays a role in memory formation. Since serotonin affects so many areas in the brain, it is natural that researchers would be interested in discovering how MDMA affects serotonin, especially in terms of how it might cause damage in to the many systems it influences.
And now for a cool picture of a serotonin molecule, courtesy of the Heffter Research Institute. If you cross your eyes in just the right way, you can see it in 3D.
Main Table of Contents