Effect of bethanechol on gastric functions in primary anorexia nervosa.

We have shown previously that patients with primary anorexia nervosa (PAN) have decreased gastric emptying and acid output. The present studies were designed to explore the possibility that bethanechol, a parasympathomimetic agent, would acutely restore normal gastric function in those patients. We used a dye dilution technique to determine acid output and fractional emptying rate in 5 patients with PAN and 11 healthy controls during a basal period and following bethanechol (0.06 mg/kg, subcutaneously). Although bethanechol caused fractional emptying and acid output to increase threefold in PAN (P less than 0.05), it failed to produce stimulation of gastric emptying and acid output to levels similar to those achieved in controls. Therefore, gastric emptying and acid output were less in PAN than in controls, both basally and after bethanechol. Since bethanechol failed to completely restore acute gastric function, the defect of emptying and acid output in PAN does not appear to be caused by a deficiency of parasympathetic neurotransmitter but, instead, could reflect undetermined inhibitory influences or impaired function of the muscular and glandular cells. Following weight gain, fractional emptying rate and acid output were still slightly less in PAN patients than in controls, but the difference was statistically significant only for basal acid output.