Novel Chloride-Dependent L-(3H)Glutamate Binding Site in Astrocyte Membranes

摘要

This study examines membranes prepared from purified astrocytes grown in culture for various glutamate binding sites. The use of membranes prepared from cultured astrocytes permits the selective characterization of a single component of the synaptic system. This experimental model should not only yield a more detailed understanding of glial interactions with excitatory transmitters, but should also contribute to the clarification of the cellular location of binding sites previously identified in heterogeneous preparations (i.e., tissue slices and homogenates of whole brain). This line of investigation was prompted by the increasingly strong evidence that glial cells are essential to the regulation of the chemical environment that surrounds neurons and synapses. This regulation could include the maintenance of ion and transmitter concentrations via ion channels, modulatory receptors, metabolic enzymes, or transport systems. Although the possible modes of regulation by glia may vary, most of the mechanisms appear dependent on the direct interaction of the transmitter with these cells.