Effects of hypoxia and other vasoactive agents on pulmonary and cerebral artery smooth muscle cells

1992.- Smooth muscle cells (SMC) were isolated from cat ce-rebral arteries and three sizes of pulmonary artery (<200-, 200-to 600-, and>800-pm diameter) and used within 72-96 h. Change in cell length in response to hypoxia and other vasoac-tive agents was measured in a specially constructed cell chamber on an inverted microscope. Pulmonary artery SMC responded to hypoxia differently according to artery size. SMC from <200-and 200- to 600-pm-diameter pulmonary arteries shortened 18.6 t 4.85 and 24.2 & 2.70%, respectively. However, SMC from>800-pm-diameter pulmonary arteries shortened 0.81-+ 0.44%. Cerebral artery SMC plated on a flexible polydimethyl siloxane membrane showed loss of tension during exposure to hypoxia. The shortening of SMC from the 200- to 600-pm pulmonary arteries was accompanied by myosin phosphorylation. SMC from>800-pm-diameter pulmonary arteries and cerebral arter-ies contained myosin that did not phosphorylate during hy