Extracellular pH in the brain during ischemia: Relationship to the severity of lactic acidosis

Abstract

On the basis of data showing a bimodal distribution of values for extracellular pH (pHe), and a discontiguous ΔPco2/Δlactate relationship, Kraig et al. (1986) proposed that H+ is grossly compartmentalized between neurons and glia in the ischemic brain. We measured ΔpHe during ischemia, varying ischemic lactate contents between 9 and 38 mmol kg-1. No bimodal distribution was found, but ΔpHe varied linearly with lactate content. Because we have also failed to record a discontinuous ΔPco2/Δlactate relationship, we conclude that major compartmentation of H+ does not occur during ischemia.