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Inhibition of vesicular glutamate storage and exocytotic release by Rose Bengal
Author(s) -
Ogita Kiyokazu,
Hirata Koji,
Bole David G.,
Yoshida Sumiko,
Tamura Yutaka,
Leckenby Anne Marie,
Ueda Tetsufumi
Publication year - 2001
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.1471-4159.2001.00200.x
Subject(s) - rose bengal , synaptic vesicle , glutamate receptor , synaptosome , neurotransmission , biophysics , chemistry , vesicle , neurotransmitter , biochemistry , biology , membrane , receptor , organic chemistry
It had been thought that quantal size in synaptic transmission is invariable. Evidence has been emerging, however, that quantal size can be varied under certain conditions. We present evidence that alteration in vesicular [ 3 H] l ‐glutamate (Glu) content within the synaptosome (a pinched‐off nerve ending preparation) leads to a change in the amount of exocytotically released [ 3 H]Glu. We found that Rose Bengal, a polyhalogenated fluorescein derivative, is a quite potent membrane‐permeant inhibitor ( K i = 19 n m ) of glutamate uptake into isolated synaptic vesicles. This vesicular Glu uptake inhibition was achieved largely without affecting H + ‐pump ATPase. We show that various degrees of reduction elicited by Rose Bengal in [ 3 H]Glu in synaptic vesicles inside the synaptosome result in a corresponding decrease in the amount of [ 3 H]Glu released in a depolarization‐ (induced by 4‐aminopyridine) and Ca 2+ ‐dependent manner. In contrast, fluorescein, the halogen‐free analog of Rose Bengal, which is devoid of inhibitory activity on vesicular [ 3 H]Glu uptake, failed to change the amount of exocytotically released [ 3 H]Glu. These observations suggest that glutamate synaptic transmission could be altered by pharmacological intervention of glutamate uptake into synaptic vesicles in the nerve terminal, a new mode of synaptic manipulation for glutamate transmission.