The purpose of this study is to determine the characteristics of colonic myoelectric and motor activity in normals and in patients with specific diseases. This five-year proposal has 4 major objectives: (1) To develop new techniques for the measurement and the electronic analysis of human colonic myoelectric activity; (2) to evaluate the specific dietary and caloric factors altering colonic function in normals; (3) to study the pathophysiology of colonic dysfunction in diabetes mellitus, scleroderma, and irritable bowel syndrome; (4) to determine the role of the ileocecal sphincter in altering colonic function. Myoelectric recordings from the proximal colon will be obtained using a new suction-micro-electrode. A special emphasis will be placed upon the use of a computer algorithm, Fast Fourier Transform, and electronic counting for the analysis of colonic myoelectrical activity. Colonic recordings will be obtained following the administration of separate dietary components at various caloric loads. These colonic responses will be compared to the responses to eating a whole meal. Colonic dysfunction in diabetes will be investigated and correlated with peripheral and autonomic neuropathy, gastric empting and clinical bowel function. The effect of emotional stress on colonic function will be evaluated in normal and irritable bowel patients. The mechanisms of action of both laxatives and antidiarrheal agents will be studied in patients with disordered myoelectrical activity. These pharmacological studies will define the mechanism by which colonic motor function may be altered. Lastly, the role of the ileocecal sphincter in controlling colonic function will be evaluated. The neurohumoral control of the sphincter will be determine, and its role in altering antegrade and retrograde flow will be ascertained. The role of this sphincter in humans will be studied.