The effect of atropine, propantheline and poldine on the vagally stimulated gastric motility and the histamine-stimulated acid gastric secretion in the rat.

Histamine-induced acid gastric secretion in the anaesthetized rat was not diminished by poldine in a dose which reduced vagally stimulated gastric contractions by approximately 75%. A dose of atropine, twice as large as the dose which reduced gastric contractions by 75%, had no apparent effect on the histamine-stimulated acid gastric secretion up to 2 hr after the injection. Only when more than 40 times as much atropine was injected did a slight inhibition of the acid secretion occur in 80 to 120 min. Propantheline, in a dose which inhibited gastric contractions by approximately 75%, slightly diminished acid secretion in 40 to 80 min. This effect was not increased by a further dose of propantheline. It was concluded that, in so far as any inhibition of acid gastric secretion had occurred, this could not be interpreted as an anti-muscarine or a direct toxic effect, but rather as an indirect effect possibly due to interference with the blood flow through the stomach wall.