EFFECTS OF VARIATIONS IN IONIC CONCENTRATIONS ON HIGH-AFFINITY UPTAKE OF L-GLUTAMATE IN NON-GLUTAMATERGIC NEURONS AND NONNEURONAL CELLS CULTURED FROM NEONATAL RAT CORTEX

被引:11
作者
BALCAR, VJ
机构
[1] Department of Anatomy, The University of Sydney, NSW 2006
关键词
D O I
10.1016/0197-0186(91)90034-B
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
High affinity uptake of L-glutamate in the CNS is known to be strongly dependent on Na+. However, the stoichiometry and the mechanism of the relationship between Na+ and L-glutamate at the putative transport site (i.e. whether one or two Na+ are co-transported with one molecule of L-glutamate and in which order they bind to the site) have been the subject of debate because the results of quantitative studies on Na+ -dependence of L-glutamate uptake have varied from one experimental model to another. This communication discusses ionic requirements of L-glutamate uptake in two culture systems derived from neonatal rat cortex - one containing no neurons and the other including, in addition to glial cells, GABAergic neurons. The present results are consistent with a model in which one molecule of L-glutamate is co-transported with either one or two Na+ and no fixed order is required for the binding of Na+ and L-glutamate to the transport site. Also, in contrast to other studies, L-glutamate uptake was found to be significantly reduced in the absence of Ca2+ and was not affected by depolarizing concentrations of K+.
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页码:43 / 49
页数:7
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