The mechanism of the inhibitory effect of gluten fractions on the peristaltic reflex.

The mechanism of the inhibitory effect of gluten fractions on the peristaltic reflex was studied using, first, a filtrate of the autoclaved peptic-tryptic digest of gluten (fraction III A.F.) and, second, the ultrafiltrate of an aqueous extract of gluten (fraction G.U.F.). The fractions did not act as antagonists to naturally-occurring agents such as acetylcholine or substance P, but they did depress the twitch response of the isolated guinea-pig jejunum preparation stimulated coaxially. The output of acetylcholine from cholinergic nerve endings in gut was decreased during rest as well as during electrical stimulation. In large amounts, the gluten fractions depressed acetylcholine synthesis in vitro. It was concluded that the mechanism of inhibition of the peristaltic reflex by gluten fractions was chiefly by decreasing acetylcholine release.