Effects of norepinephrine on the dog common carotid, coronary and renal arteries: in vitro studies

The effects of norepinephrine were studied on segments of the common carotid, left circumflex and renal arteries of dogs with the endothelium intact and removed. Norepinephrine induced a dose-dependent increase in tension in segments of the renal and carotid artery but did not produce any effect on the coronary artery. Although the absence of endothelium did not affect the magnitude of the norepinephrine-induced vasoconstriction of the renal artery, it elicited a more pronounced response in the carotid artery in which the endothelium was removed. Our data suggest that the vascular response to norepinephrine is dependent upon the specific arterial bed and, secondly, that the endothelium plays a determinant role in the magnitude of the response of the carotid artery.