Effects of ricinoleic and oleic acids on the digestive contractile activity of the canine small and large bowel.

Oleic and ricinoleic acids or their trans isomers, elaidic and ricinelaidic acids, were administered intraduodenally and evaluated for their effects on the digestive motor activity of the canine small and large bowel. Four dogs of mixed breed were implanted with duodenal cannulas and extraluminal strain gage transducers along the circular axis of the proximal and mid-jejunum, terminal ileum, and proximal colon. After feeding 200 g of canned dog food to induce continuous contractile activil of isotonic saline was given into the duodenum as a single bolus infusion and recordings were made for a 1-hr period. A 30-ml volume of saline served as control. Administration of each cis fatty acid produced an initial stimulation in jejunal areas of about a 2-min duration followed by a post-stimulatory inhibition. Both the initial stimulation and post-stimulatory inhibition were greater for ricinoleic acid than for oleic acid. Minimal or no effects were produced in ileal or colonic areas. In contrast, the trans isomers produced little or no effect on either the small or large bowel. Alterations in the digestive contractile patterns produced by oral administration of 10 ml of oleic, ricinoleic acid or their respective triglycerides were also tested. Triolein had no effects. Ricinoleic acid and castor oil poduced a brief initial stimulation followed by polonged inhibition of small bowel motor activity. Both cathartics had a mild laxative effect. Digestive motor patterns returned to control approximately 45 min after oleic acid. There was no indication at any time of an initiation of continuous contractile activity after ricinoleic acid or castor oil which could justify the use of the terms irritant of stimulant to describe their actions.