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 system based on in situ hybridization. Strong signals were detected in brain, spinal cord and retina. Expression of EAAC1 was particularly strong in pyramidal cells of the cerebral cortex, pyramidal cells of the hippocampus, mitral cells of the olfactory bulb, various thalamic nuclei and cells of certain retinal layers. EAAC1 was also expressed in non-glutamatergic neurons such as GABAergic cerebellar Purkinje cells and a-motor neurons of the spinal cord. We propose that EAAC1 is not only involved in the sequestration of glutamate at glutamatergic synapses and in protecting neurons from glutamate excitotoxicity, but also in the cellular metabolism involving glutamate.