The Role of Serotonin and Substance P

Serotonin and Substance P are important neurotransmitters, and key factors in understanding Fibromyalgia

A neurotransmitter is a substance that passes signals or information across the synapse (junction) that separates one nerve cell from another. Neurotransmitters are stored in the nerve cell’s end. When an electrical impulse travels down the nerve cell, it causes the release of the neurotransmitter, which then travels across the synapse and either promotes or inhibits continued electrical impulses along the nerve. Serotonin is involved in multiple functions that regulate and influence:

  • Sleep cycles
  • Mood
  • Learning
  • Pain perception
  • Immune system

Serotonin production takes place in the brain and the gastrointestinal tract. Fibromyalgia is one of the conditions that are known as “Low Serotonin Syndromes“. Regulation of serotonin metabolism takes place during the deep or therapeutic sleep patterns.With the sleep disturbances of Fibromyalgia, the metabolic regulation is disrupted. This causes further immune system dysfunction due to the role serotonin plays in the activation of natural killer cells. Compounding the sleep disturbance is the fact that since serotonin helps induce deep sleep, its low levels then further aggravate the inability to achieve this desired sleep pattern.

How Substance P Works with Serotonin and Affects Pain Perception in Fibromyalgia

There is another neurotransmitter called substance P, which works together with serotonin. Substance P is responsible for:

  • Transmitting pain impulses to the brain and spinal cord.
  • Producing a nerve generated impulse that dilates blood vessels.
  • Causing fluid and proteins to migrate from the cells to outside the cells.

Low serotonin levels can cause elevated substance P levels in Fibromyalgia

These elevated levels, sometimes three times greater in people with Fibromyalgia, could explain the increased pain perception. Evidence from studies suggests that “low serotonin syndrome” and the symptoms of Fibromyalgia are strongly associated. Females have a lower capacity to produce serotonin than men. This fact may help explain the fact that over 90% of Fibromyalgia sufferers are female. When events occur that produce the “low serotonin syndrome”, this lessened capability to produce serotonin could be a crucial component in the greater female susceptibility to the onset of symptoms.