Mass peristalsis in the human colon after contact with oxyphenisatin
Colonic motility was assessed using time-lapse cinefluorography and intraluminal pressure recordings, both before and after rectal administration of a mixture containing barium sulphate and oxyphenisatin. These studies revealed various patterns of colonic movement. Oxyphenisatin was shown to selectively induce a form of progressive mass propulsion that was indistinguishable from natural mass peristalsis. As little as 0.5 mg of the drug, when dispersed throughout the pelvic and distal descending colon, was sufficient to trigger a peristaltic response, while higher doses increased the frequency of these movements. A standard 4 mg dose induced mass peristalsis in 82% of subjects, provided the drug made adequate contact with the colonic mucosa. Typically, the response occurred within 20 minutes. Subjects who were more sensitive exhibited a greater number of peristaltic events and shorter response times. In 73% of those who responded, peristaltic activity ceased between 25 and 40 cm from the anal verge. In cases where peristalsis extended further, the individuals often had shortened distal colons. The effectiveness of oxyphenisatin in inducing peristalsis dropped sharply beyond approximately 45 cm from the anus, with the highest efficacy observed in the proximal descending colon.