Serotonin Neurotransmitter Function

Serotonin is one of the neurotransmitters. Its effects are mainly related to the nervous system (mood), the cardiovascular system (vasoconstriction – vasoconstriction) and the intestine (intestinal peristalsis ↑).It is synthesized from the amino acid tryptophan.

To check serotonin levels in the blood, the breakdown product 5-hydroxyindoleacetic acid (HIES) is determined from urine.

The procedure

Material needed

  • 24h collection urine (acidified with HCL).
  • Specify the amount of urine collected

Preparation of the patient

  • Three days before and during the collection of urine, the following drugs should be avoided, as they distort the results:
    • Acetylsalicylic acid (ASA).
    • Chlorpromazine
    • Methamphetamine
    • Methocarbamol
    • Mephenesin carbamate
    • Paracetamol
    • Reserpine
  • Three day before and during the collection of urine, the following food and beverages should be avoided, as they distort the results:
    • Fruits such as pineapples, avocados, bananas, currants, kiwis, melons, mirabelles, plums, gooseberries, plums.
    • Vegetables such as eggplant, tomatoes
    • Pecans nuts, walnuts
    • Cheese
    • Cocoa
    • Coffee
    • Nicotine

Disruptive factors

  • See preparation of the patient

Standard values

Normal value <9.0 mg/24h

Indications

  • Suspected carcinoid tumor (see below).
  • Mental disorders

Interpretation

Interpretation of increased values

  • Epilepsy
  • Carcinoid tumor (synonyms: Carcinoid syndrome, neuroendocrine tumors, NET) – tumors originating from the neuroendocrine system; they are predominantly located in the appendix/appendix appendix (appendiceal carcinoid) or bronchi (bronchial carcinoid); other localizations include the thymus (thymic carcinoid), ileum/ruminal intestine (ileal carcinoid), rectum/foregut (rectal carcinoid), duodenum/duodenal intestine (duodenal carcinoid), and stomach (gastric carcinoid); typical symptoms are characterized by the triad of diarrhea (diarrhea), flushing (flushing), and Hedinger syndrome (heart valve damage); serotonin levels > 40 mg/24 h are probative of carcinoid
  • Celiac disease (gluten-induced enteropathy) – chronic disease of the mucosa of the small intestine (small intestinal mucosa) due to hypersensitivity to the cereal protein gluten.

Interpretation of lowered values

  • Anxiety
  • Burnout syndrome
  • Depression
  • Migraine