Changes in gastro-intestinal motility induced by cholera toxin and experimental osmotic diarrhoea in dogs: effects of treatment with an argillaceous compound.

Effects on digestive motility of two agents which induce diarrhoea were investigated in conscious dogs chronically fitted with strain-gauge transducers sutured to the serosa of the antrum, the jejunum and the proximal colon and with a catheter inserted into the duodenum. Effects were tested before, during and after treatment with an argillaceous compound, smectite, at a dose of 100 mg/kg/day for 6 days. Smectite treatment alone induced only minor changes in gastric motility with a decrease in the motility index and an increase in the duration of the post-prandial disruption of gastric migrating motor complexes (MMCs). Intraduodenal administration of cholera toxin (200 micrograms) before smectite treatment disrupted MMCs on the stomach and the jejunum for more than 10 h without affecting colonic motility. These effects were still seen when cholera toxin was administered on the 3rd day of smectite treatment but were partially antagonized on the 6th day of treatment. Intraduodenal infusion of a hypertonic mannitol solution (900 mosm/l, 6 ml/min for 1 h) transiently disrupted gastric and jejunal MMCs, stimulating colonic motility for more than 6 h and inducing abundant diarrhoea 45-60 min after the beginning of the infusion. When the mannitol infusion was repeated on the 3rd and 6th days of smectite, gastric and jejunal motor disturbances persisted while colonic hyperactivity was abolished and onset of diarrhoea was delayed by more than 8 h. We thus conclude that smectite treatment has an antidiarrhoeal effect, partially antagonizing digestive motor disturbances induced by two agents used to provoke experimental diarrhoea.