Endothelium-dependent pressure-induced contraction of isolated canine carotid arteries.

Experiments were conducted in a bioassay system, where a canine coronary artery ring without endothelium (bioassay tissue) was superfused by the effluent from a perfused canine carotid artery segment with endothelium (donor segment). A rapid increase in transmural pressure (from near 0 to 32-38 mmHg) triggered active contraction of the donor segment and simultaneously of the bioassay tissue. These contractions were prevented by removal of the endothelium from the donor segment but not by treatment of the segment with indomethacin. Exposure to elevated pressure depressed basal, acetylcholine-, and flow-induced release of endothelium-derived relaxing factor(s). Methylene blue prevented the pressure-induced contraction of the bioassay ring. These data show that pressure-induced contraction of isolated carotid arteries is endothelium dependent and is mediated by the depression of the synthesis and/or release of endothelium-derived relaxing factor(s).