ELECTRICAL COUPLING BETWEEN SMOOTH-MUSCLE CELLS AND ENDOTHELIAL-CELLSIN PIG CORONARY-ARTERIES

The control of smooth muscle cells by endothelial cells has been well established by the identification of vasoactive factors released by th e endothelial cells. In contrast? the possibility that smooth muscle c ells influence the endothelial cells has been considered rarely. Some results suggest possible electrical communication between the smooth m uscle and the endothelial cells but proof is lacking. We therefore tes ted for electrotonic conduction of signals from smooth muscle cells to endothelial cells. The endothelium was removed from half of a strip o f porcine coronary artery. In a partitioned chamber, rectangular hyper polarization or depolarization was applied to the de-endothelialized r egion by field stimulation. The resulting membrane potential changes i n the smooth muscle cells spread electrotonically along the media into the area with intact endothelium. We recorded from endothelial cells to determine whether this electrical signal spreads into endothelial c ells. Hyperpolarization or depolarization initiated in smooth muscle c ells was recorded consistently in endothelial cells. This demonstrates a functional electrotonic propagation from smooth muscle to endotheli al cells.