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 smal l herniations of the colonic mucosa, through the external muscle coats of t he 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 act ivity could be found to help explain the etiology and symptoms of the disea se. Methods: Electric activity was studied by extracellular electrodes on t issues from both the circular and the longitudinal muscle of the colon from 12 patients. Results: In tissues from 10 patients a distinctly abnormal re sponse to cholinergic stimulation was observed. A characteristic developmen t of bursts of action potentials did not develop; instead, slow-wave activi ty of relatively low frequency was maintained throughout the period of stim ulation. This slow-wave activity showed a lack of synchronization. Conclusi ons: The results indicate that, in diverticular disease, local changes in e lectric activity occur that change the response to cholinergic stimulation. When this happens, development of periodic bursts of action potentials nor mally associated with propulsive activity do not develop, favoring segmenta l contractile activity associated with low-frequency slow-wave activity.