Inhibition of lactate export by quercetin acidifies rat glial cells in vitro

The relationship between glial lactate release and glial intracellular pH (pH i) regulation is studied using C6 glioma cells and rat astrocytes in vitro, and the lactate transport inhibitors quercetin and a-cyano-4-hydroxycinnamate (CHC). pHi is measured using 2′,7′bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF). The results show that lactate release is mediated partly by a specific lactate transport system inhibitable by quercetin (50 mM), but not by CHC (5 mM). Inhibition by quercetin results in a significant 3‐4-fold increase of intracellular lactate and a decrease of intracellular pH to 6.9. A participation of quercetin-inhibitable lactate transport in glial pHi-regulation is suggested…