Ion, transmitter and drug effects on energy metabolism in astrocytes

Abstract

Publisher Summary This chapter describes the effects of individual ions and transmitters known to stimulate energy metabolism in astrocytes. It discusses the general mechanisms involved and the potential role of glycogen metabolism during brain activation. Effects of some drugs interact with ion and transmitter effects on brain metabolism are also discussed in this chapter. The chapter reviews that the accumulation of K + in astrocytes by stimulation of the extracellular K + -sensitive site of the Na + , K + -ATPase, and by activation of the Na + , K + , 2Cl - , cotransporter plays a major role in ion homeostasis and therefore, in energy metabolism in the central nervous system (CNS). Several transmitters affect energy metabolism in astrocytes by Ca 2+ -mediated stimulation of mitochondrial dehydrogenases and glutaminase, and by the activation of the breakdown of glycogen, likely to serve as a rechargeable energy substrate in peripheral processess of the astrocytes, which are too thin to contain any mitochondria. Certain drugs classically assumed to act solely on neurons owe a substantial part of their effect to interactions with the effects of ions or transmitters on astrocytes, thereby altering energy metabolism in astrocytes, and thus in the brain.