Mass peristalsis in the human colon after contact with oxyphenisatin.
Colonic motility studies using time-lapse cinefluorography and intraluminal pressure recording before and after the introduction per rectum of a mixture of barium sulphate and oxyphenisatin solution show the different forms of movement of the colonic contents. Oxyphenisatin was found to be a selective actuator of a form of progressive mass propulsion indistinguishable from spontaneous mass peristalsis. Less than 0.5 mg distributed through the pelvic and distal descending colon was enough to produce a peristaltic response; larger quantities tended to increase the number of resulting movements.A standard dose of 4 mg of the drug was followed by mass peristalsis in 82% of the subjects in whom it came into adequate contact with colonic mucosa. The response usually took place within 20 minutes. The more sensitive the subject, the greater was the number of peristaltic responses and the shorter the interval before the response began. In 73% of the subjects who responded, the mass peristalsis came to a halt between 40 and 25 cm from the anal margin, and many of those in whom it extended farther appeared to have shortened distal colons. The likelihood of the drug giving rise to peristalsis diminished abruptly distal to about 45 cm from the anus; its effectiveness was greatest in the proximal descending colon.