Abstract

Magnesium sulphate, a substance known to cause release of cholecystokinin (CCK) from the small intestinal mucosa, was given by mouth (dose 0·1g/kg in 150 ml water) to 20 patients with the irritable bowel syndrome. A rapid increase in colonic segmental motor activity (onset within two to six minutes in most cases) was seen (percentage activity increased from 16·2 to 23·7 p<0·05; mean wave amplitude from 7·1 to 9·1 cm H₂O, NS; motility index from 144 to 259, p<0·01). This increase was most marked in 10 patients who complained of attacks of abdominal pain after food (16·1 to 29·8%, p<0·01; 6·8 to 9·6 cm H₂O, p<0·05; 135 to 350, p<0·05), and after the magnesium sulphate three of these patients experienced an attack of their usual pain. These findings provide further evidence that `functional' abdominal pain after food may in some cases be related to an exaggerated intestinal motor response to cholecystokinin.