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Uptake of l ‐Glutamate into Rat Brain Synaptic Vesicles: Effect of Inhibitors that Bind Specifically to the Glutamate Transporter
Author(s) -
Roseth Svein,
Fykse Else Marie,
Fonnum Frode
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.65010096.x
Subject(s) - bumetanide , glutamate receptor , chemistry , evans blue , bafilomycin , non competitive inhibition , synaptic vesicle , biophysics , biochemistry , transporter , pharmacology , vesicle , ion transporter , biology , membrane , enzyme , endocrinology , receptor , gene , apoptosis , autophagy
In this study we have described a series of new and potent inhibitors of the vesicular uptake of glutamate. The two most efficient inhibitors were the dyes Evans blue and Chicago Skye Blue 6B, which are structurally related to glutamate and were competitive inhibitors in the nanomolar range. The anion channel blocker 4,4′‐diisothiocyanostilbene‐2,2′‐disulfonic acid (SITS) and the diuretics furosemide and bumetanide are inhibitors of chloride transport in other organs but were competitive inhibitors of glutamate and noncompetitive with respect to chloride ions. Evans blue, Chicago Skye Blue 6B, SITS, furosemide, and bumetanide are all large organic acids with two centers of negative charge and an electron‐donating group at close vicinity of the negative charge at physiological pH. The inhibition of the glutamate uptake with these inhibitors was noncompetitive with respect to Cl − . The inhibitors, therefore, probably interact directly with the glutamate carrier. Bafilomycin A 1 , which is a specific vacuolar ATPase inhibitor, was used as a control and inhibited the vesicular dopamine, glutamate, and GABA uptake to the same extent. None of the inhibitors had any effect on the plasma membrane carrier, which is therefore clearly different from the vesicular carrier.