Regional deafferentation down-regulates subtypes of glutamate transporter proteins

J Neurochem. 1995 Dec;65(6):2800-3. doi: 10.1046/j.1471-4159.1995.65062800.x.

Abstract

Low extracellular glutamate content is maintained primarily by high-affinity sodium-dependent glutamate transport. Three glutamate transporter proteins have been cloned: GLT-1 and GLAST are astroglial, whereas EAAC1 is neuronal. The effects of axotomy on glutamate transporter expression was evaluated in adult rats following unilateral fimbria-fornix and corticostriatal lesions. The hippocampus and striatum were collected at 3, 7, 14, and 30 days postlesion. Homogenates were immunoblotted using antibodies directed against GLT-1, GLAST, EAAC1, and glial fibrillary acidic protein and assayed for glutamate transport by D-[3H]aspartate binding. GLT-1 immunoreactivity was decreased within the ipsilateral hippocampus and striatum at 14 days postlesion. GLAST immunoreactivity was decreased within the ipsilateral hippocampus and striatum at 7 and 14 days postlesion. No alterations in EAAC1 immunoreactivity were observed. D-[3H]Aspartate binding was decreased at 14 days postlesion within the ipsilateral hippocampus and at 7 and 14 days postlesion within the ipsilateral striatum. By 30 days postlesion, glutamate transporters and D-[3H]aspartate binding returned to control levels. This study demonstrates the down-regulation of primarily glial, and not neuronal, glutamate transporters following regional disconnection.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ATP-Binding Cassette Transporters / metabolism*
  • Afferent Pathways / physiology
  • Amino Acid Transport System X-AG
  • Animals
  • Biological Transport
  • Cerebral Cortex / physiology*
  • Corpus Callosum / physiology*
  • Denervation
  • Hippocampus / physiology*
  • Immunoblotting
  • Male
  • Rats
  • Rats, Sprague-Dawley

Substances

  • ATP-Binding Cassette Transporters
  • Amino Acid Transport System X-AG