Theories of nausea and vomiting

on 23.12.09 with 1 comment

  • The main area in the brain responsible for vomiting is the vomiting center
  • This area is located in the lateral reticular formation of the medulla
  • It receives input from many areas:
    • Chemoreceptor trigger zone
      • Located in the floor of the 4th ventricle in the area postrema
      • It picks up circulating chemical in the blood
      • It is important because it lies outside the BBB, therefore, circulating toxins (e.g.bacterial food poisoning toxins, chemotherapy) can cause vomiting, even though they do not pass through the BBB
    • Vestibular apparatus
    • Tractus solitarius
      • vagal afferents from the gut, heart and testes
      • Direct input from gut (reflex)

It is important to know the receptors involved in the emetic response

  • On the CTZ:
    • 5HT3
    • D2
  • On the vagal afferents:
    • 5HT3
  • In the vomiting center
    • Muscarinic
    • H1 receptors

Category: Medical Subject Notes , Pharmacology Notes



gh said...
May 6, 2010 at 9:41 PM

NK 1 (neurokinin 1) - antagonist aprepitant is also used in chemotherapy induced vomiting .
steroids (dexamethasone) also are anti emetics

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