Electrical coupling in longitudinal colonic smooth muscle

This study investigates the nature of electrical coupling between cells and estimates the passive electrical parameters of the longitudinal colonic smooth muscle. Gaussian white noise measurements and analysis techniques are used to obtain the input impedance function of a strip of smooth muscle from the dog colon. A system model approach based on a network model is used to investigate different coupling mechanisms. A gradient method of optimization is then used to fit the analytical input impedance of the network model to the measured input impedance. Our results indicate that the longitudinal colonic smooth muscle may be composed of many groups of cells; while cells are tightly coupled within a group, different groups are weakly coupled by resistive and capacitive components.