Comparative analysis of sodium-dependent L-glutamate transport of synaptosomal and astroglial membrane vesicles from mouse cortex.
Uptake of [3H]L-glutamate into membrane vesicles prepared from either mouse cortical astrocyte cultures or synaptosomes was found to be an electrogenic sodium- and potassium-dependent transport process with saturable uptake kinetics. Pharmacological differences were revealed by using a variety of substrate analogues. L-trans-PDC inhibited the synaptosomal glutamate transport 2-4-fold stronger than the astroglial uptake. The substrate analogues DL-threo-beta-hydroxy-aspartate, DL-aspartate-beta-hydroxamate, L-aspartate and D-aspartate inhibited glutamate transport of astroglial and neuronal membrane vesicles in a distinctive manner, whereas D-glutamate, quisqualate and dihydrokainate had no effect in either case. Immunoblotting and immunocytochemical labeling with antibodies against the rat brain glutamate transporter revealed the selective reaction of a band at about 75 kDa mol. wt. and a specific pattern of astrocyte immunostaining.
Rauen
T
T
Department of Animal Physiology, University of Osnabrück, Germany.
Jeserich
G
G
Danbolt
N C
NC
Kanner
B I
BI
D027322:Amino Acid Transport System X-AG; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D005971:Glutamates / Q000378:metabolism*; D006023:Glycoproteins / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D012964:Sodium / Q000494:pharmacology*; D013574:Synaptosomes / Q000378:metabolism*
D027322:Amino Acid Transport System X-AG; D005904:Glial Fibrillary Acidic Protein; D005971:Glutamates; D006023:Glycoproteins; D012964:Sodium