Intercellular coupling mediated by potassium accumulation in peg-and-socket junctions

Coupling of smooth muscle cells is important for coordination of gastrointe stinal motility. Small structures called peg-and-socket junctions (PSJs) ha ve been found between muscle cells and may play a role in electrical coupli ng due to extracellular potassium accumulation in the narrow deft between t he muscle cells. A model was developed in which an electrical boundary elem ent model of the cell morphology is used in conjunction with a finite diffe rence model which described ionic fluxes and diffusion of extracellular pot assium in the PSJ, The boundary element model used a combination of triangu lar and cylindrical elements to reduce computational demand while ensuring accuracy, Barrier kinetics were used to model the underlying ionic transpor t mechanisms. Seven ionic transport mechanisms were used to create the tran smembrane voltage waveform. Results indicate that PSJs may produce signific ant coupling between smooth muscle cells under appropriate conditions. Coup ling increased exponentially with increasing length and with decreasing int ercellular gap.