GLUTAMATE RECEPTORS IN CORTICAL PLASTICITY - MOLECULAR AND CELLULAR BIOLOGY

Glutamate receptors (GluRs) provide the major excitatory input to cort ical neurons. Four main subtypes of GluRs are distinguished, namely, N -methyl-D-aspartate, alpha-amino-3-hydroxy-5-methylisoxzole-4-propioni c acid, kainate, and metabotropic receptors. All of them have been imp licated in neuronal plasticity, and this paper reviews data that may b e pertinent to the role played by GluRs in neocortical plasticity both in adult animals as well as during postnatal development. Emphasis is given to receptor distribution analyzed by various means, such as phy siological responses, ligand binding as revealed by receptor autoradio graphy, and expression of receptor subunits at both mRNA and protein ( immunoreactivity) levers. Possible mechanisms of involvement of GluRs in plastic changes on cortical neuron response are reviewed, and data on up- and downregulation of GluRs in neocortical plasticity are summa rized. Functional studies involving either activation or blocking, and effects of such manipulation on cortical plasticity are discussed.