Glutamate transport in cultures from developing avian cerebellum: presence of GLT-1 immunoreactivity in Purkinje neurons.
Immunocytochemical studies indicated that Purkinje cells cultured from chick embryonic cerebellum (embryonic day 8) strongly express a glutamate transporter EAAT2 cloned from human brain (GLT-1 in rat brain). At both 7 days and 14 days in culture, Purkinje neurons accumulated 1 microM [3H]L-glutamate via a potent "high-affinity" transport system that could be inhibited by D- and L-threo-3-hydroxyaspartate (D- and L-t-3OHA) and by L-trans-pyrrolidine-2,4-dicarboxylate (L-t-PDC). The order of potency of the three inhibitors was L-t-PDC approximately L-t-3OHA > D-t-30HA. Only the value of IC50 (concentration causing 50% inhibition) for D-t-3OHA significantly changed between 7 days (116 microM) and 14 days in culture (40 microM). All nH approximately 1, except in the case of the inhibition by D-t-3OHA at 14 days in culture (nH = 0.57), indicating the possible appearance of heterogeneity of the transport sites at later stages of culturing. Chronic inhibition of L-glutamate transport by L-t-PDC resulted in major changes in the morphology of Purkinje cells; particularly, the neurites almost completely regressed.
Meaney
J A
JA
Children's Medical Research Institute, Wentworthville, Australia.
Balcar
V J
VJ
Rothstein
J D
JD
Jeffrey
P L
PL
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D027322:Amino Acid Transport System X-AG; D000818:Animals; D001692:Biological Transport; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000196:embryology*; D002642:Chick Embryo; D018698:Glutamic Acid / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011689:Purkinje Cells / Q000378:metabolism*
D018528:ATP-Binding Cassette Transporters; D027322:Amino Acid Transport System X-AG; D009419:Nerve Tissue Proteins; D018698:Glutamic Acid