Analysis Of Mechanism Underlying The Hemorheologic Changes Induced By Coronary Occlusion In Dogs And Experimental Study Of Effects Of Hemodilution On Myocardial Ischemia

It has long been demonstrated both in clinical observations and experimental researches that hemorheologic change is one of the most important reactions to myocardial ischemia. However, the mechanism underlying the changes is still uncertain. In order to clarify the role of nerve reflex activated by coronary occlusion in hemorheologic changes which appear during myocardial ischemia, we studied the effect of blocking the sympathetic reflex on abnormal heraorheologic changes induced by coronary occlusion. Besides, to demonstrate whether improving blood fluidity can alleviate the myocardial ischemia, we observed the effects of hemodilution with dextran-40 or fluorocarbon emulsion(FCE) on myocardial ischemia.Experiments were performed on anesthetized open-chest dogs.The main projects are:1.Observe the changes in Hct(microhematocrit centrifuge), Fib(heat precipitation method), η, and η,(NXE-I cone-ptate viscometer) following LAD occlusion and compare the hemorheologic changes of blood from systemic circulation(BSC) with that of blood from coronary vein which drains ischemic region(BIR).2.Investigate the role of sympathetic reflex in hemorheologic changes by (1) application of lidocaine on the left ventricular epicardial surface to prevent the generation and conduction of impulses from nerve ending located in ischemic myocardium, (2) bilateral section of stellate ganglia to block the efferent impulses to heart, (3) bilateral section of the splanchnic nerves to block the sym-pathetico-adrenal connection and (4) infusion of epinephrine(E) after bilateral section of the splanchnic nerves to clarify the role of adrenal mudulla secre-...