The Effect of Deoxygenation Rate of the Erythrocyte on Oxygen Transport to the Cardiac Muscle
Up to the present time O2 delivery to the cardiac muscle has been studied theoretically by many authors (1, 2, 11, 12) using a Krogh’s cylinder model. However, relatively little attention has been paid to the influence of deoxygenation of red blood cells (RBC) on the O2 delivery. Mochizuki (8) measured the O2 dissociation rate of oxygenated hemoglobin and RBC by using a rapid flow method, and found that the deoxygenation rate of RBC was proportional to the PO2 difference between RBC and surrounding medium, suggesting that the diffusion inside RBC and across the cell membrane was a rate limiting factor. The rate factor, Fc’, which is given by dividing the O2 quantity taken up by 1 ml RBC by the PO2 difference between RBC and surrounding medium, was 0.02 – 0.03 sec-1•mmHg-1. Recently, Tazawa et al (10) reported that the deoxygenation rate of RBC in the chorioallantoic capillary of chick embryos ranged from 0.008 to 0.009 sec-1•mmHg-1. In contrast to our observations, Lawson and Forster (5) previously described that the PO2 difference between RBC and plasma in tissue was negligibly small, when the rate factor measured by them in a RBC suspension mixed with hydrosulfite (4) was used.
KeywordsCardiac Muscle Rate Factor Disc Model Cylinder Model Deoxygenation Rate
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