Comparison of Direct Effects of Angiotensin and Other Vasoactive Agents on Small and Large Blood Vessels in Several Vascular Beds

ATHOROUGH STUDY of a vasoactive agent should inelude effects on resistance to blood flow (influences arterial pressure and rate of blood flow), storage of blood (influences effective eircuilating volume and, hence, venous return, cardiac output, and arterial pressure), capillary patency (iinfluences diffusion distances and, therefore, rates of movement of material and heat), and filtration pressure (influences storage of water in tissues). This paper presents a comparison of the local effects of angiotensin and other vasoactive agents on resistance to blood flow through the dog forelimb and gut beds and on C"filtration pressure" in the dog forelimb and rabbit ear. Preliminary observations on blood storage in the dog forelimb are also mentioned. Inasmuch as the data contained in the paper were derived from a number of studies conducted over the last 10 years, the methods utilized are summarized as each study is presented.