Flow-induced responses in cat isolated pulmonary arteries

Shimoda, Larissa A., Nan A. Norins, and Jane A. Madden. Flow-induced responses in cat isolated pulmonary arteries. J. Appl. Physiol. 83(5): 1617–1622, 1997.—Isolated, cannulated, endothelium-intact cat pulmonary arteries, averaging 692 ± 104 μm in diameter, were set at a transmural pressure of 10 mmHg and monitored with a video system. Intraluminal flow was increased in steps from 0 to 1.6 ml/min by using a syringe pump. An electronic system held pressure constant by changing outflow resistance. Flow-diameter curves were generated in physiological saline solution. At constant transmural pressure, the arteries constricted in response to increased intraluminal flow. Constriction was not affected by removing extracellular Ca 2+ but was abolished after treatment with ryanodine to deplete intracellular Ca 2+ stores, with the endothelin-1 synthesis inhibitor phosphoramidon, with the endothelin A-receptor antagonist BQ-123, with the protein kinase C inhibitor staurosporine, or with glutaraldehyde to reduce endothelial cell deformability. The results indicate that isolated pulmonary arteries can constrict in response to intraluminal flow and suggest that constriction is mediated by endothelin-1 and depends on intracellular Ca 2+ release and protein kinase C activation.