pH environment of red cells in the spleen

LEVESQUE, M. J. AND A. C. GROOM. pH environment of red ceLLs in the spleen. Am. J, Physiol. 231(6): 1672-1678. 1976. Intrasplenic pH in vivo was deduced from measurements on blood drained from cat spleen during contraction with the inflow occluded. The pH of blood in the red pulp is normally 7.20, but stasis or reduced flow through the pulp causes pH to fall toward 6.8. The splenic pulp contains blood of high hematocrit. To evaluate the role of buffering by the red cells themselves, intrasplenic pH in red cell-free spleens was, therefore, estimated as well. This was done from measurements on perfusates of pH 6.4-N entering and leaving the spleen during red cell washout. At inflow pH ~6.8 the outflow pH was raised, at inflow pH = 6,8 there was no change, but at inflow pH >6.8 the outflow pH was lowered. These results indicate that the pH environment of red cells in the spleen results from the interplay of two separate factors: i) pH-determining elements of the splenic tissue that buffer at 6.8, and ii) buffering provided by red cells passing through the pulp.