Arteriolar,Capillary,and Venular FITC—Dextran Time—Concentration Curves and Plasma Flow Velocities

Summary

A method is described for determining plasma flow velocity in microvessels of the cat mesentery. Time-concentration curves of FITC-dextran were recorded from the video-tape-recorded images of fluorescent dye as it passes through the vessels. The plasma velocity in arterioles, capillaries, and venules were determined during control periods and during isoproterenol vasodilation. Vasodilation reduces the mean transit time of the indicator from the point of injection to the arterioles, capillaries, and venules. Plasma velocity is markedly increased by isoproterenol vasodilation. There is evidence of reduced dispersion of indicator by the microvessels with vasodilation.