Glutamate receptors in microglia.

Expression of functional glutamate receptors (GluR) on glial cells in the developing and mature brain has been recently established. Over the last decade there has been physiological, molecular and biochemical evidence suggesting the presence of GluR on microglia. However, the significance of GluR activation in microglia remains largely unknown. In this review, we discuss the expression of GluR on microglia and the effect of GluR activation on microglial function. Microglia are the resident immune cells of the central nervous system, and activation of GluR in them has been shown to regulate their immunological response which may be either neuroprotective or neurotoxic. Microglial activation is known to initiate a myriad of molecular events such as nitric oxide production, free radicals generation, disruption of calcium regulation and release of proinflammatory cytokines, proteases, neurotransmitters, and excitatory amino acids, primarily glutamate. Since microglial activation has been implicated in several neuropathologies, an understanding of the pathway coupled to the various microglial GluR will help to develop therapeutic interventions for ameliorating microglia-mediated damage.