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Seratonin

Explanations > Brain stuff > Brain chemistry > Neurotransmitters > Seratonin

Composition | Function | Dysfunction | See also

Seratonin, or 5-hydroxytryptamine (5-HT), is a monoamine. Its adjective is serotonergic.

Composition

Chemically, seratonin is created in seratonergic neurons in the CNS.

Serotonin is synthesized from tryptophan by the enzyme tryptophan hydroxylase (TPH), which produces 5-hydroxytryptophan (5-HTP) and then the action of 5-HTP decarboxylase to create 5-HT.

Sertonergic neurons are mostly found in the raphe nuclei of midbrain, pons and medulla.

There are nine types of seratonertic receptors with varying effect, for example 5-HT_1B and 5-HT_1D are presynaptic autoreceptors. All receptors are metabotropic, except for the ionotropic 5-HT_1A.

Function

Seratonin provides a wide range of control of emotions and the body, including anger, aggression, body temperature, pain, mood, sleep, dreaming, human sexuality, appetite, and metabolism. It also stimulates vomiting.

A common pattern in some seratonin-involved activities appears to be compulsion and urge.

Seratonin has also been linked with contentment and satisfaction.

Dysfunction

Drugs

There are drugs that are agonist and antagonist for all types of serotonergic receptors.

p-chlorophenyalanine (PCPA) is an antagonist, blocking the effect of TPH.

Fluoxetine (Prozac) inhibits reupdate of seratonin and is used in treatment of depression, anxiety and

Fenfluramine stimulates the release of seratonin and is used as an appetite suppressant in treating obesity.

Lysergic acid diethylamide (LSD) is a narcotic that distorts hallucinogenic visual perception is a direct agonist of 5-HT_2A receptors in the forebrain.

Methylenedioxymethamphetamine (MDMA) or 'Ecstasy' has excitatory and hallucinogenic and is an agonist for both seratonin and norepinephrine. It makes noradrenergic and serotonergic transporters to operate backwards, increasing neurotransmitter release and inhibiting reupdate. MDMA action on sertonoergic transporters causes hallucinations but can also damage them.