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Na + ‐dependent high‐affinity uptake of l ‐glutamate in cultured fibroblasts
Author(s) -
Balcar Vladimir J.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80846-9
Subject(s) - chemistry , glutamate receptor , biochemistry , microbiology and biotechnology , biology , receptor
Uptake of 1 μM[ 3 H] l ‐glutamate by cultured 3T3 fibroblasts was strongly dependent on extracellular Na + ; it was reduced by elevated concentrations of K + (60 mM) but it was not influenced by variations in the concentration of Ca 2+ (0–9.6 mM). d ‐ and l ‐Asparate, d ‐ and l ‐ threo ‐3‐hydroxyaspartate dl ‐ threo ‐3‐methylaspartate and a few other glutamate derivatives and analogues inhibited the uptake but several close analogues of l ‐glutamate (including d ‐glutamate) had no effect, implying that the uptake system is highly structurally selective. The recently identified inhibitor of glutamate uptake in synaptosomal preparations, l ‐ trans ‐pyrrolidine‐2,4‐dicarboxylate, was also among the inhibitors. Apparent K m of the uptake was found to be < 10 μM. The present observations indicate that Na + ‐dependent ‘high‐affinity’ uptake of l ‐glutamate may appear in structures which are apparently unrelated to glutamatergic synaptic transmission in the CNS.