Effect of some gastrointestinal hormones on motor and electrical activity of the digestive tract in the conscious cat

Abstract

Three peptides structurally related to gastrin and known to be full agonists of antral motility in the conscious cat, pentagastrin (PG), cholecystokinin (CCK) and synthetic octapeptide of cholecystokinin (OP-CCK), were compared in relation to antral and duodenal electrical activity. They induced the same antral effect in eliciting an increase in the basal electrical rhythm (BER) and a short-lasting decrease in the frequency of the bursts of spikes. The electrical changes were correlated with lumen pressure changes measured in parallel, consisting of a decrease in the frequency of high-amplitude peaks and an increase in low-amplitude peaks. The additive effect of PG and CCK shows that the peptides are full agonists for antral electrical activity, as they are for antral motility and acid secretion. In contrast to the antrum, the three peptides increased the frequency of the duodenal spike bursts, CCK and OP-CCK decreased the BER frequency, while PG increased BER slightly. The increase in antral and duodenal BER obtained after a beef-liver meal, which produced a large endogenous gastrin release, suggests a major role for gastrin in antral motility induced by feeding, at least in the cat.