Gastric emptying

The passage of gastric contents from the stomach into the small intestine is influenced by many factors:

• content of the meal - content of food material in the duodenum influences the rate of gastric emptying. The calorific value of the food seems to be the major determinant of inhibition of gastric motility, ie fats are the most inhibitory.
• hyperglycaemia - this reduces vagal tone to the stomach and thus slows gastric emptying
• peptides that are associated with delayed gastric emptying include gastrin, cholecystokinin, vasoactive intestinal polypeptide and gastric inhibitory peptide.
• abdominal pain and bowel distension are associated with delayed gastric emptying.
• atrophic gastritis is associated with a delayed gastric emptying.
• vagotomy - this reduces gastric emptying - in this situation the gastric intrinsic nerves remain intact and still release acetylcholine in response to drugs such as metoclopramide
• drugs e.g. anti-parkinsonism drugs cause delayed gastric emptying by blocking cholinergic muscuranic receptors and by being dopamine agonists
• dumping syndrome - this results in accelerated gastric emptying and results from the emptying of hyperosmolar nutrients into the small intestine.

Note that a succusion splash may accompany delayed gastric emptying.