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.
- Glycogen phosphorylase