Effects of Vasoactive Drugs on Blood Flow in Rabbits: Photoplethysmographic Assessment

Chung, Moon Sang; Lo, Min; Chung, Min Young; Lee, Han Koo; Lee, Sang Hoon

Abstract

The dynamic blood flow is regulated by the numerous complex mechanisms. Since blood flow varies directly with the radius of the vessel, blood flow is markedly affected by small changes in the caliber of the vessels. Using the hotoplethysmography, we assessed the relative changes of blood flow after topical application of the vasoactive drugs to the femoral arteries of the rabbits. It is the purpose of this study to evaluate the immediate and delayed effects of the vasoactive drugs such as epinephrine, methylergonovine, chymopapain, and lidocaine in course of time when the drugs applied topically to the vessel. 60 rabbits were divided into 6 experimental groups. In group I, the femoral artery was surgically exposed only. In Group g-A, epinephrine was applied to the femoral artery after surgical exposure. In Group Il-B, after spplication of epinephrine, the effect of epiniphrine was reversed with lidocaine. Another drugs were applied as follows methylergonovine in Group Hl-A, methylergonovine and lidocaine in Group Ill-B as in group Il-B, Chymopapain in Group lV. The relstive changes of blood flow were measured by the photoplethymograph for 3 weeks. The results are as follows ; 1. The amplitude of the photoplethysmographic wave decreased immediately after the topical application of epinephrine, methylergonovine and chymopapain. Such an effect could be observed until the 3rd week after the topical application of the drugs, 2. The delayed dffect of reducing the amplitude could be seen during the 1st week in the epinephrine and methylergonovine treated groups. However, it was seen after 1st week in the chymopapain treated group. 3. The delayed effect of epinephrine and methylergonovine could be reversed with lidocaine. 4. It seems that lidocaine can be used clinically to preyent the delayed effect of epinephrine and methylergonovine.