PT  - JOURNAL ARTICLE
AU  - Guang Jian Wang
AU  - Hye Joo Chung
AU  - Jamie Schnuer
AU  - Kara Pratt
AU  - Anthony C. Zable
AU  - Michael P. Kavanaugh
AU  - Paul A. Rosenberg
TI  - High Affinity Glutamate Transport in Rat Cortical Neurons in Culture
AID  - 10.1124/mol.53.1.88
DP  - 1998 Jan 01
TA  - Molecular Pharmacology
PG  - 88--96
VI  - 53
IP  - 1
4099  - http://molpharm.aspetjournals.org/content/53/1/88.short
4100  - http://molpharm.aspetjournals.org/content/53/1/88.full
SO  - Mol Pharmacol1998 Jan 01; 53
AB  - We assayed glutamate transport activity in cultures of rat cortical neurons containing <0.2% astrocytes. Using [3H]l-glutamate as the tracer, sodium-dependent high affinity glutamate transport was demonstrated [K m = 17.2 ± 2.4 μm; V max = 3.3 ± 0.32 nmol/mg of protein/min (n = 5)]. Dihydrokainate (1 mm) inhibited uptake of radioactivity by 88 ± 3% and had aK i value of 65 ± 7 μm. l-α-Aminoadipate (1 mm) inhibited uptake by only 25 ± 4%.l-trans-2,4-Pyrrolidine dicarboxylate,l-serine-O-sulfate, and kainate potently inhibited transport activity withK i values of 5.1 ± 0.3, 56 ± 6, and 103 ± 9 μm, respectively (n = 3). Voltage-clamp studies of GLT1-expressing oocytes showed that, as in cortical neurons, glutamate transport was not inhibited by l-α-aminoadipate. Dihydrokainate was a potent inhibitor (K i = 8 ± 1 μm), andl-serine-O-sulfate produced a GLT1-mediated current with a K mvalue of 312 ± 33 μm. Immunoblot analysis showed that neuronal cultures express excitatory amino acid carrier 1 (EAAC1), shown previously to be relatively insensitive to dihydrokainate, plus a trace amount of GLT1, but no GLAST. These studies establish that a major component of the glutamate transport activity of cortical neurons is dihydrokainate sensitive and distinct from the previously recognized neuronal transporter excitatory amino acid carrier 1.