title: Alteration of GABA transporter expression in the rat cerebral cortex following needle puncture and colchicine injection.
abstract: In the adult cerebral cortex, GABA transporters (GATs) are expressed by both neurons and astrocytes. GAT-1 immunoreactivity is found in axon terminals of GABAergic neurons and astrocytes, while GAT-3 immunolabeling occurs only in the latter. The present study was designed to determine whether the expression of GAT-1 and GAT-3 in the adult rat cerebrum changes after needle lesion and colchicine infusion. Following a needle puncture or a saline injection, immunolabeling for GAT-1 and GAT-3 was slightly increased in an area around the needle track. Not only was the neuropil labeling for both GATs increased, but also a few neuronal somata were found to be immunoreactive for GAT-1. Colchicine injections induced a striking increase in immunolabeling for both GATs in the neuropil in an area adjacent to the needle path and surrounding it. A homologous region of the contralateral hemisphere also showed a moderate increase of immunoreactivity in the neuropil for both GATs. Furthermore, this contralateral site showed many neuronal somata immunolabeled for GAT-1. These changes were mainly detected during the first 5 days following intracortical lesions. These results indicate that (1) the upregulation of GAT-1 and GAT-3 in cortical interneurons and astrocytes is caused by both mechanical and chemical factors associated with the injections; (2) increased GAT-1 and GAT-3 expression contralateral to the site of colchicine injection is mediated by transcellular signaling across the corpus callosum; and (3) the lesion-induced GAT expression may play a protective role by helping to balance excitatory and inhibitory neuronal activities.
authors.affiliation: Department of Anatomy and Neurobiology, University of California at Irvine, Irvine, CA 92697-1275, USA.
authors.forename: X X
authors.initials: XX
authors.lastname: Yan
authors.forename: C E
authors.initials: CE
authors.lastname: Ribak
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000032:analysis*; D002540:Cerebral Cortex / Q000737:chemistry / Q000187:drug effects*; D003078:Colchicine / Q000494:pharmacology*; D005260:Female; D050485:GABA Plasma Membrane Transport Proteins; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000032:analysis*; D026901:Membrane Transport Proteins; D009339:Needles; D009419:Nerve Tissue Proteins / Q000032:analysis*; D027361:Organic Anion Transporters; D011677:Punctures; D051381:Rats; D017207:Rats, Sprague-Dawley; D015996:Survival Rate; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D050485:GABA Plasma Membrane Transport Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D027361:Organic Anion Transporters; C493415:Slc6a1 protein, rat; D005680:gamma-Aminobutyric Acid; D003078:Colchicine