NEURONAL HIGH-AFFINITY GLUTAMATE TRANSPORT IN THE RAT CENTRAL-NERVOUS-SYSTEM

EAAC1 is a neuronal and epithelial high affinity glutamate transporter previously cloned from rabbit intestine. Here we report the isolation of EAAC 1 from rat brain and its expression in the central nervous s ystem based on in situ hybridization. Strong signals were detected in brain, spinal cord and retina. Expression of EAAC1 was particularly st rong in pyramidal cells of the cerebral cortex, pyramidal cells of the hippocampus, mitral cells of the olfactory bulb, various thalamic nuc lei and cells of certain retinal layers. EAAC1 was also expressed in n on-glutamatergic neurons such as GABAergic cerebellar Purkinje cells a nd alpha-motor neurons of the spinal cord. We propose that EAAC1 is no t only involved in the sequestration of glutamate at glutamatergic syn apses and in protecting neurons from glutamate excitotoxicity, but als o in the cellular metabolism involving glutamate.