Affiliation:
1. Department of Physiology, School of Medicine, University of Virginia Charlottesville, Virginia 22901
Abstract
The changes in microvascular diameter and perivascular oxygen tension resulting from alterations in suffusion solution Po
2
were investigated in a study of the participation of oxygen in the regulation of blood flow. Diffusion gradients for oxygen were altered by changing the Po
2
of a solution covering the surface of the hamster cheek pouch. As the solution Po
2
was raised from a low of 11 mm Hg, perivascular Po
2
of the large arterioles initially decreased to a minimum at approximately 40 mm Hg and then increased progressively as solution Po
2
was elevated further. Arterial capillary and tissue Po
2
remained relatively constant over a range of solution oxygen tensions between 11 and 40 mm Hg, suggesting that either the precapillary sphincters or the terminal arterioles were active in regulating tissue Po
2
as the input of O
2
from the solution was increased. The arterioles constricted as solution Po
2
was elevated. Average arteriolar diameter decreased by 13% as solution Po
2
increased from 11 to 47 mm Hg. A more pronounced constriction of 20% occurred when solution Po
2
was increased from 11 to 84 mm Hg. These experiments indicated that the response of large and small arterioles was not mediated by a direct effect of oxygen on the vascular smooth muscle, since decreases in perivascular oxygen tension were coincident with decreases in vascular diameter in these vessels over a range of solution Po
2
between 11 and 47 mm Hg. The data did not distinguish between a direct and an indirect effect of oxygen on the vascular smooth muscle of the terminal arterioles and precapillary sphincters. However, the oxygen tensions measured at these sites (18-30 mm Hg) required that the vascular smooth muscle cells respond to altered oxygen tension at levels higher than those which have been demonstrated experimentally.
Publisher
Ovid Technologies (Wolters Kluwer Health)
Subject
Cardiology and Cardiovascular Medicine,Physiology
Cited by
184 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献