Anatomy

Serotonin

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Serotonin, Serotoninergic, 5-Hydroxytryptamine, 5-HT

  • Physiology
  1. Neurotransmitter
    1. Motor control
    2. Pain Perception
    3. Sympathetic Nervous System outflow
  2. Synthesis from Essential Amino Acid L-Tryptophan
  3. Serotonin is released from inhibitory Neurons originating in the pons and Midbrain raphe nuclei
    1. Serotonin is also stored in the Small Intestine enterochromaffin cells (contains 90% of the body's Serotonin stores)
  4. Serotonin Receptors
    1. Serotonin-1 Receptor (5-HT-1) Activity
      1. Anti-depressant effect
    2. Serotonin-2 Receptor (5-HT-2) Activity
      1. Inhibits 5-HT-1 Receptor
      2. Sexual Dysfunction
      3. Insomnia
      4. Anxiety
    3. Serotonin-3 Receptor (5-HT-3) Activity
      1. Gastrointestinal symptoms
      2. Headache
  • Medications
  • Increase Serotonin levels
  1. Increased Serotonin synthesis: L-Tryptophan
  2. Decrease Serotonin metabolism: MAO Inhibitors
  3. Increase Serotonin release: Amphetamines, Cocaine
  4. Inhibit Serotonin uptake
    1. Tricyclic Antidepressants: Amitriptyline
    2. Selective Serotonin Reuptake Inhibitor (SSRI): Prozac
    3. Other: Meperidine, Dextromethorphan
  5. Direct Serotonin Receptor Agonists: Buspar, Imitrex, Lysergic Acid Diethlyamide (LSD)
  6. Dopamine Agonists: Amantadine, Wellbutrin, Levodopa
  7. Other Non-specific Serotonin increase: Lithium
  • References
  1. Olson (2020) Clinical Pharmacology, MedMaster, Miami, p. 35