Electrophysiological studies of the smooth muscle cell membrane of the rabbit common carotid artery.

The electrical responses of the smooth muscle cells of the rabbit common carotid artery to extracellular stimulation were studied in isotonic and hypertonic solution (1.7 times normal tonicity) with microelectrodes. No spontaneous electrical or mechanical activity was recorded when the tissue was in either isotonic or hypertonic solution. The voltage-current relation of smooth muscle cells in the common carotid artery showed marked rectification in both isotonic and hypertonic solutions. In isotonic and hypertonic solutions mean values for membrane potentials were -44.5 and -51.5 mv, for space constants 1.13 and 1.21 mm, and for time constants 212.2 and 238.2 msec, respectively. Addition of 34.3 mM TEA to the solutions caused spontaneous action potentials in the common carotid artery. The action potentials recorded simultaneously from two microelectrodes showed good synchronization. It was concluded that there is electrical transmission between cells of this artery.