Ability of rat microglia to uptake extracellular glutamate.
Since it has been suggested that microglia in vivo act as glutamate scavengers, this possibility was investigated in primary cultured microglia. The microglia showed specific abilities to uptake (14)C-glutamate depending on incubation time and numbers of cells used. The activity was suppressed by a specific inhibitor for a glial cell-type transporter, glutamate transporter-1 (GLT-1) (EAAT2). However, that of cultured astrocytes was not affected. These results suggest that microglia uptake glutamate by means of GLT-1. Supporting these results, immunoblotting revealed the presence of GLT-1 in the microglia, while only glutamate-aspartate transporter (GLAST) (EAAT1: another glial cell-type transporter) was detected in the astrocytes. All together, these results indicate that microglia can act as glutamate scavengers in vivo by expressing the glutamate transporter GLT-1.
Nakajima
K
K
Institute of Life Science, Soka University, 1-236 Tangi-machi, Hachioji, 192-8577, Tokyo, Japan. nakajima@t.soka.ac.jp
Tohyama
Y
Y
Kohsaka
S
S
Kurihara
T
T
D018528:ATP-Binding Cassette Transporters / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D027322:Amino Acid Transport System X-AG; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D002478:Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002490:Central Nervous System / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005110:Extracellular Space / Q000187:drug effects* / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism* / Q000493:pharmacokinetics; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051381:Rats
D018528:ATP-Binding Cassette Transporters; D027322:Amino Acid Transport System X-AG; D002250:Carbon Radioisotopes; D004791:Enzyme Inhibitors; D018698:Glutamic Acid