EFFECTS OF LOW ALVEOLAR OXYGEN AND HIGH ALVEOLAR CARBON DIOXIDE ON THE RATE OF FLOW OF CEREBROBROSPINAL FLUID

Abstract

In 50 experiments the effects of the administration of gaseous mixtures high in CO2 and low in O on the rate of flow of cerebrpspinal fluid (CSF) were studied in dogs. High CO2 mixtures, whether administered with ventilation under physiological control, or with constant artificial ventilation, caused a decided increase in the rate of flow of CSF. With normal ventilation low O caused a marked decrease in the flow of CSF followed in prolonged administrations by an increase approaching the normal rate. With constant artificial ventilation low O caused an increase in the flow of CSF. The changes in flow observed are believed to be due primarily to changes in the rate of formation of the fluid, though they may be complicated by other factors. The fact that the flow of CSF in its response to the administration of these gases resembles salivary secretion but differs from lymph flow, suggests a secretory mechanism of formation of the fluid. It is suggested that these changes in flow can be explained on the basis of changes in acidity of the cells of the choroid plexus, assuming that increasing acidity increases the rate of formation of CSF, and vice versa.