L-glutamate-induced swelling of cultured astrocytes is dependent on extracellular Ca2+.
L-Glutamate (L-Glu)-induced swelling of astrocyte cultures from rat brain was examined by determining [3H]O-methyl-D-glucose ([3H]OMG) uptake. Time-course of the L-Glu (0.5 mM)-induced increase in [3H]OMG space of astrocytes showed two phases; about 30% increase was obtained in 10 min and the increased [3H]OMG space was steady up to 20 min. Then, the [3H]OMG space was further increased during the incubations longer than 30 min. In Ca2(+)-free conditions, while the time-course up to 20 min was similar to that in the normal condition, the increase in [3H]OMG space by further incubations was not shown. The L-Glu-increased [3H]OMG space persisted for 2 h in a L-Glu-free medium and thereafter turned to the normal level in 4 h. In contrast, the incubation in a L-Glu-free medium for 30 min reversed the increased [3H]OMG space in the absence of extracellular Ca2+. These results indicate that swelling of astrocytes induced by L-Glu is characterized by an accompanied influx of Ca2+.
Koyama
Y
Y
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Osaka University, Suita, Japan.
Baba
A
A
Iwata
H
H
D019325:3-O-Methylglucose; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000494:pharmacology*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000502:physiology*; D005971:Glutamates / Q000494:pharmacology*; D007700:Kinetics; D008757:Methylglucosides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D005971:Glutamates; D008757:Methylglucosides; D019325:3-O-Methylglucose; D002118:Calcium