The neurophysiology of vomiting

Area of Science:

• Neuroscience
• Gastroenterology
• Pharmacology

Background:

• Nausea and vomiting are triggered by diverse stimuli including pregnancy, space travel, raised intracranial pressure, radiation, and cytotoxic drugs.
• The precise mechanisms linking these stimuli to the emetic reflex remain incompletely understood.
• Traditional models focus on a chemoreceptor trigger zone and a brainstem vomiting center, requiring revision with new research.

Purpose of the Study:

• To provide a comprehensive overview of the neurophysiology of emesis, including nausea and retching.
• To explore the biological functions of these emetic phenomena.
• To examine the role of visceral systems and vagal mechanisms in gut motor activity during emesis.

Main Methods:

• Review of existing literature on the neurophysiology of emesis.
• Analysis of the 'vomiting center' concept, including the parvocellular reticular formation.
• Detailed consideration of radiation and cytotoxic drug-induced emesis mechanisms.

Main Results:

• Emesis involves complex neurophysiological pathways beyond simple gastrointestinal events.
• Vagal mechanisms significantly influence gut motor activity during nausea and vomiting.
• The 'vomiting center' may be a distributed network rather than a single anatomical locus.

Conclusions:

• Understanding the neurophysiology of emesis is crucial for managing various related conditions.
• Novel 5-HT-3 receptor antagonists show promise in treating radiation and cytotoxic drug-induced vomiting.
• Further research into these mechanisms will advance antiemetic therapies.