EXTRACELLULAR PH IN THE BRAIN DURING ISCHEMIA - RELATIONSHIP TO THE SEVERITY OF LACTIC-ACIDOSIS

On the basis of data showing a bimodal distribution of values for extracellular pH (pH(e)), and a discontinuous DELTA-PCO2/DELTA-lactate relationship, Kraig et al. (1986) proposed that H+ is grossly compartmentalized between neurons and glia in the ischemic brain. We measured DELTA-pH(e) during ischemia, varying ischemic lactate contents between 9 and 38 mmol kg-1. No bimodal distribution was found, but DELTA-pH(e) varied linearly with lactate content. Because we have also failed to record a discontinuous DELTA-PCO2/DELTA-lactate relationship, we conclude that major compartmentation of H+ does not occur during ischemia.