serotonin

Examples of serotonin in the following topics:

• Hallucinogens

  • Hallucinogens affect the levels of serotonin or glutamate in the brain and are divided into psychedelics, dissociatives, and deleriants.
  • Most psychedelics work by interacting with serotonin receptors in the brain.
  • LSD, also a psychedelic, blocks serotonin from the brain, which regulates mood, perception, muscle contraction, and other cognitive functions.
  • LSD blocks serotonin because it is, structurally, similar to serotonin.
  • For this reason, the brain mistakes LSD for serotonin and directs it to the synaptic cleft (instead of actual serotonin).

• Neurodevelopmental Disorders: Mental Illnesses

  • Some research supports the "classic monoamine hypothesis," which suggests that depression is caused by a decrease in norepinephrine and serotonin neurotransmission.
  • For example, monoamine oxidase inhibitors (MAO inhibitors) block the enzyme that degrades many neurotransmitters (including dopamine, serotonin, norepinephrine), resulting in increased neurotransmitter in the synaptic cleft.
  • Selective serotonin reuptake inhibitors (SSRIs) block the reuptake of serotonin into the presynaptic neuron.
  • This blockage results in an increase in serotonin in the synaptic cleft.
  • Other types of drugs, such as norepinephrine-dopamine reuptake inhibitors and norepinephrine-serotonin reuptake inhibitors, are also used to treat depression.

• Obsessive-Compulsive Disorder

  • Studies have implicated about two dozen potential genes that may be involved in OCD; these genes regulate the function of three neurotransmitters: serotonin, dopamine, and glutamate (Pauls, 2010).
  • OCD has been linked to abnormalities with the neurotransmitter serotonin, although this could be either a cause or an effect of OCD.
  • Serotonin is thought to have a role in regulating anxiety.
  • The serotonin receptors of OCD sufferers may be under-stimulated, which is consistent with the observation that many OCD patients benefit from the use of selective serotonin reuptake inhibitors (SSRIs), a class of medications that allows more serotonin to be readily available.

• Seasonal Affective Disorder and Jet Lag

  • One possibility is that SAD is related to a lack of serotonin, and serotonin polymorphisms could play a role in SAD, although this is disputed.
  • Mice incapable of turning serotonin into N-acetylserotonin (by Serotonin N-acetyltransferase) appear to express "depression-like" behavior, and antidepressants such as fluoxetine increase the amount of the enzyme Serotonin N-acetyltransferase, resulting in an antidepressant-like effect.

• Stress and Disease

  • Serotonin transmission from both the caudal raphe nuclei and rostral raphe nuclei is reduced in patients with depression compared with non-depressed controls.
  • Increasing the levels of serotonin in these pathways by reducing serotonin reuptake, hence increasing serotonin function, is one of the therapeutic approaches to treating depression.

• Premature Ejaculation

  • It is believed that the neurotransmitter serotonin plays a central role in modulating ejaculation.
  • Therefore, it is perceived that low level of serotonin in the synaptic cleft in these specific areas in the brain could cause premature ejaculation.
  • This theory is further supported by the proven effectiveness of selective serotonin reuptake inhibitors, which increase serotonin level in the synapse, in treating premature ejaculation.

• Generalized Anxiety Disorder

  • Pharmaceutical treatments for GAD include selective serotonin reuptake inhibitors (SSRIs), which are more commonly used as antidepressants.
  • SSRIs block the reabsorption of serotonin in the brain so that it can keep activating serotonin receptors, improving the individual's mood.
  • SSRIs (selective serotonin reuptake inhibitors) are a type of drug frequently used to treat disorders with symptoms of depression (e.g., major depressive disorder) and anxiety.

• Types of Neurotransmitters by Function

  • Biogenic amines include the catecholamines, such as dopamine, norepinephrine (NE), and epinephrine, as well as indolamines such as serotonin and histamine.
  • Serotonin is synthesized  from tryptophan.

• Platelet Plug Formation

  • The released chemicals include ADP, VWF, thromboxane A2, platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), serotonin, and coagulation factors.
  • Serotonin is a short-lived inflammatory mediator with a vasoconstrictive effect that contributes to vascular changes associated with inflammation during an injury.

• Stimulants

  • MDMA also has many physical side effects: since MDMA increases the activity of serotonin, the brain becomes depleted of serotonin, causing a rebound sadness or depression in the days following use.
  • MDMA differs from most stimulants in that its primary pharmacological effect is on the neurotransmitter serotonin rather than dopamine, epinephrine, or norepinephrine.