Regulatory mechanisms for glycogenolysis and K+ uptake in brain astrocytes

Recent advances in brain energy metabolism support the notion that glycogen in astrocytes is necessary for the clearance of neuronally-released K ⁺ from the extracellular space. However, how the multiple metabolic pathways involved in K⁺-induced increase in glycogen turnover are regulated is only partly understood. Here we summarize the current knowledge about the mechanisms that control glycogen metabolism during enhanced K ⁺ uptake. We also describe the action of the ubiquitous Na ⁺/K⁺ ATPase for both ion transport and intracellular signaling cascades, and emphasize its importance in understanding the complex relation between glycogenolysis and K⁺ uptake.