Transient focal ischemia triggers neuronal expression of GAT-3 in the rat perilesional cortex.
We studied the expression of gamma-aminobutyric acid plasma membrane transporters GAT-1 and GAT-3 in the cerebral cortex of rats following transient middle cerebral artery occlusion. GAT-1 immunoreactivity exhibited minor changes and immunoblotting studies showed that the protein levels were unchanged. By contrast, GAT-3 immunoreactivity, which is normally expressed exclusively by distal astrocytic processes, was remarkably altered: (1) GAT-3-positive puncta were reduced in the perilesional cortex and disorganized in the remaining regions; (2) numerous GAT-3-positive cells were observed, mostly in the perilesional cortex; they were all NeuN positive and most of them were identified as pyramidal neurons. Immunoblotting studies showed that GAT-3 levels were not significantly altered. Confocal studies showed that virtually all GAT-3-positive neurons in the perilesional cortex were TUNEL negative and coexpressed heat shock protein 70 kDa. These findings suggest that ischemia triggers a novel neuronal expression of GAT-3 that is greatest in the perilesional cortex and may contribute to the reported reduction in GABAergic inhibition.
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism* / Q000473:pathology; D050485:GABA Plasma Membrane Transport Proteins; D005786:Gene Expression Regulation / Q000502:physiology*; D002546:Ischemic Attack, Transient / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D026901:Membrane Transport Proteins / Q000096:biosynthesis* / Q000235:genetics; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley
D050485:GABA Plasma Membrane Transport Proteins; D026901:Membrane Transport Proteins; C493415:Slc6a1 protein, rat