Study of the inhibitory effect of lead acetate on duodenal contractility in rat.

1. Abdominal colic and constipation are symptoms of lead poisoning in man, but mechanisms of these effects are not yet fully understood. In this study the effect of lead acetate on contractility of rat duodenum was determined in vivo in 70 rats. 2. Rats were orally dosed with 44 mg/kg per day lead as 53 mmol/L lead acetate, for 4 weeks. Motility of the duodenum was recorded with an electrical impedance probe. 3. A significant decrease in the amplitude of contraction waves in case of treated rats was observed compared with controls which received an equal volume of saline. The number of contractions increased from 26 per min in controls to 33 per min in treated rats. Gastrointestinal transit rate decreased by 64% and 69% after 9 and 15 days of lead exposure, respectively.