Evaluation of L-glutamate clearance capacity of cultured rat cortical astrocytes.
Astrocytes have a function in the uptake of excitatory neurotransmitter L-glutamate via the glutamate transporter. To evaluate the L-glutamate clearance capacity of astrocytes, we developed a colorimetric method for the determination of L-glutamate concentration and measured changes in extracellular L-glutamate concentration in rat cortical astrocyte cultures. When L-glutamate (50-200 microM) was added to astrocyte cultures and incubated for 1-8 h, the extracellular L-glutamate concentration declined with time. When L-glutamate was mixed with astrocyte culture supernatants only, no significant change in L-glutamate concentration was observed, ruling out the possibility that L-glutamate is spontaneously or enzymatically degraded in the extracellular space. Alternatively, the time-dependent decline of extracellular L-glutamate concentration was blocked by the presence of glutamate uptake inhibitors, indicating that the glutamate uptake system of astrocytes plays a major role in the clearance of extracellular L-glutamate.
Abe
K
K
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, The University of Tokyo, Japan.
Abe
Y
Y
Saito
H
H
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D003124:Colorimetry; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005562:Formazans; D018698:Glutamic Acid / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013778:Tetrazolium Salts
D018691:Excitatory Amino Acid Antagonists; D005562:Formazans; D013778:Tetrazolium Salts; C079782:MTT formazan; D018698:Glutamic Acid