In vitro studies on single beating rat heart cells. II. Intercellular communication.

Summary 1. Rat heart cells separated by trypsin and grown in vitro continue to beat. 2. Cells beating at an independent rate become synchronous upon physical contact, indicating that the communication of rate of beating is through protoplasmic contact. 3. The rate of beating for the synchronous net of muscle cells is determined by the fastest beating cell. 4. Despite the superimposed rate, each cell retains potentially its own inherent rate of beating.