Sennosides and human colonic motility.

The effects of stimulant laxatives on colonic motility in man still remain controversial. Stimulation of peristalsis or a decrease of intraluminal pressure has been described manometrically after intraluminal administration of laxatives including senna. In contrast to manometry, electromyographic methods using an endoluminal probe enable continuous colonic motor recordings over a long colonic segment for at least 24 h, and consequently studies following the course of laxative effects after oral administration, the classical therapeutic route, are possible. Preliminary results using sennosides obtained with few subjects provide evidence for an increase in propulsive activity expressed as an increased number of migrating long-spike bursts in the left and sigmoid human colon. This motor colonic pattern seems to be a common feature in nonspecific or induced diarrhoea.