A study of elastic properties of a 550-µ artery in vitro

¹ Department of Anatomy, University of British Columbia, Vancouver, Canada

A technique is described for mounting a 3-cm length of the rat tail artery (550 µ o.d.) in a way that permits fluid to flow through its lumen. The diameter of the segment was measured at increasing intraluminal pressures and flow rates. Normally the artery segment distended with increasing pressures up to 100 mm Hg, but when 0.5 µg/ml norepinephrine was perfused it constricted to a radius which remained constant over this pressure range. "Elastic diagrams" were constructed from the distensibility curves for the artery wall with and without active drug-induced tension. From the linear part of the diagram, Young's modulus was calculated to be 4.5 x 10⁵ dynes/cm² for the wall and 0.8 x 10⁵ dynes/cm² for the "resting" smooth muscle (75% of wall) of the wall. The significance of wall elasticity with respect to the state of the artery in situ is discussed.