Effect of substance P on the membrane potential of coronary arterial endothelial cells in situ.

The membrane potential of the endothelial cells on a strip of pig coronary artery was recorded. The fluorescent dye lucifer yellow was injected into the recorded cell in order to prove its identity. We show that substance P transiently hyperpolarized these cells. The function of the endothelial cell hyperpolarization could be important for the role played by the endothelium and the kinins in inflammation.