Astrocytes as Regulators of Synaptic Function

Abstract

The emerging role of astrocytes in neural communication represents a conceptual challenge. In striking contrast to the rapid and highly space- and time-constrained machinery of neuronal spike propagation and synaptic release, astroglia appear slow and imprecise. Although a large body of independent experiments documents active signal exchange between astrocytes and neurons, some genetic models have raised doubts about the major Ca²⁺-dependent molecular mechanism routinely associated with release of “gliotransmitters.” A limited understanding of astrocytic Ca²⁺ signaling and the imperfect compatibility between physiology and experimental manipulations seem to have contributed to this conceptual bottleneck. Experimental approaches providing mechanistic insights into the diverse mechanisms of intra-astrocyte Ca²⁺ signaling on the nanoscale are needed to understand Ca²⁺-dependent astrocytic function in vivo. This review highlights limitations and potential advantages of such approaches from the current methodological perspective.