Microdialysis and advances for sampling synaptic and extrasynaptic pools

Intercellular communication plays a key role in information processing in the nervous system, to immune response, to cellular growth and differentiation, and to most processes fundamental to life for multicellular organisms. As a sampling technique microdialysis enables in vivo studies of brain and other tissues and has advanced our understanding of intercellular signal processing. The first part of this chapter is an overview of microdialysis in the context of a how-to-guide with reference to sampling extrasynaptic glutamate and GABA using conventional methodology. The limitations and challenges associated with sampling the synaptic pool of fast neurotransmitters are then addressed. The last part of this chapter presents ideas of advancing the microdialysis technique that may bring the microdialysis membrane closer to the synapse.