Mechanism of intercellular synchronization in the rabbit sinus node.

A strip of tissue cut from the sinus node, 0.5 mm wide, was studied in a sucrose gap chamber. With the gap width of 0.6--1.5 mm the 2 ends of the preparation showed nonsynchronous activity. Synchronization could be re-established by a shunt resistor, 15--100 k omega, connected across the gap, suggesting that synchronous firing of the sinus node requires local circuit currents.