Glucose metabolites in the striatum of freely behaving rats following infusion of elevated potassium

The outcome of patients with traumatic brain injury (TBI) can be predicted by the extracellular potassium concentration and the change in energy homeostasis. In this study, the authors investigated the effects of high potassium concentrations on extracellular levels of glucose, pyruvate and lactate in the rat striatum. Applying artificial cerebrospinal fluid (ACSF) enriched with 120 mM potassium by reverse microdialysis leads to an increase in lactate and reduction in glucose and pyruvate. Consequently, the lactate to pyruvate ratio was also increased. These data are discussed in the context of recent studies on lactate/pyruvate conversion and the potential mechanisms whereby high potassium could affect this equilibrium. We conclude that ischemic-like events are unlikely to explain these K+-induced changes.