Evidence for ionic coupling between MDCK cells at non-confluent and confluent stages of culture

The possibility of current flow between epithelial cells (MDCK) has been evaluated using intracellular electrophysiological techniques. We report here that a significant electrotonic coupling was found in this material at all ages of culture. This observation contrasts with previous reports that confluent MDCK are not ionically coupled and lack gap junctions. Alternative mechanisms for such coupling are considered, with emphasis on the role of tight junctions, should the absence of gap junctions be confirmed.