DISTRIBUTION OF mRNA CODING FOR CALCIUM PERMEABLE AND IMPERMEABLE AMPA RECEPTOR SUBUNITS DURING OVINE CNS DEVELOPMENT. |[bull]| 1763

Introduction: Following birth asphyxia, extracellular CNS levels of glutamate or other related excitatory amino acids rise and cause overstimulation of glutamate receptors. This leads to a rise in intracellular calcium which triggers a cascade of events ultimately causing neuronal cell death. The AMPA glutamate receptor has been cloned and consists of four subunits (GluR A-D) that can be expressed in alternatively spliced isoforms termed flip and flop. AMPA receptors are assembled from several subunits. The GluR-B subunit, whether expressed alone or in combination with other subunits, forms ion channels that are calcium impermeable. This unique property of the AMPA receptor places it in a pivotal position with regard to hypoxic-ischemic brain damage.