ION FLUXES ASSOCIATED WITH EXCITATORY AMINO-ACID-TRANSPORT

被引:472
作者
WADICHE, JI [1 ]
AMARA, SG [1 ]
KAVANAUGH, MP [1 ]
机构
[1] OREGON HLTH SCI UNIV, HOWARD HUGHES MED INST, PORTLAND, OR 97201 USA
关键词
D O I
10.1016/0896-6273(95)90159-0
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Flux of substrate and charge mediated by three cloned excitatory amino acid transporters widely expressed in human brain were studied in voltage-clamped Xenopus oocytes. Superfusion of L-glutamate or D-aspartate resulted in currents due in part to electrogenic Na+ cotransport, which contributed 1 net positive charge per transport cycle. A significant additional component of the currents was due to activation of a reversible anion flux that was not thermodynamically coupled to amino acid transport. The selectivity sequence of this ligand-activated conductance was NO3- > l(-) > Br- > Cl- > F-. The results suggest that these proteins mediate both transporter- and channel-like modes of permeation, providing a potential mechanism for dampening cell excitability, in addition to removal of transmitter.
引用
收藏
页码:721 / 728
页数:8
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