Abnormal Response to Cholinergic Stimulation in the Circular Muscle Layer of the Human Colon in Diverticular Disease

BACKGROUND: Diverticular disease is characterized by the occurrence of small herniations of the colonic mucosa, through the external muscle coats of the colon. The muscle wall is thickened, high intraluminal pressures can be recorded, and often constipation develops. The aim of the present study was to investigate whether an abnormality in the electric myogenic control activity could be found to help explain the etiology and symptoms of the disease. METHODS: Electric activity was studied by extracellular electrodes on tissues from both the circular and the longitudinal muscle of the colon from 12 patients. RESULTS: In tissues from 10 patients a distinctly abnormal response to cholinergic stimulation was observed. A characteristic development of bursts of action potentials did not develop; instead, slow-wave activity of relatively low frequency was maintained throughout the period of stimulation. This slow-wave activity showed a lack of synchronization. CONCLUSIONS: The results indicate that, in diverticular disease, local changes in electric activity occur that change the response to cholinergic stimulation. When this happens, development of periodic bursts of action potentials normally associated with propulsive activity do not develop, favoring segmental contractile activity associated with low-frequency slow-wave activity.