In vivo investigations on microcirculatory disturbances induced by crenated erythrocytes following norepinephrine application

Summary

Using a special apparatus for high resolution cinephotomicrography, which allows simultaneous observation and recording of microcirculatory changes, alterations in blood flow patterns and in red cell shape during norepinephrine acting have been studied. Under physiological conditions, and during slowing of capillary blood flow due to gradual removing of 20–25% of the circulating blood volume, the normal red cells are extremely deformable while passing through mesenteric capillaries. After application of norepinephrine a general arteriolar constrictive response in the bowel wall occurs, causing a further slowing of the capillary blood flow in the mesentery. Under these circumstances the erythrocytes, being in closer contact with the surrounding tissues, alter their cell shape during norepinephrine acting. Shrinkage of nearly all red cells in the mesentery occurs. This crenation effect yields distinct disturbances in microcirculation. The rigid and crenated red cells sometimes are densely packed or aggregated and often stasis arises. The red cell shapes normalize shortly after termination of norepinephrine acting. This side effect of catecholamines must be considered during therapeutic uses of catecholamines or in shock, when elevated levels of catecholamines occur.