Please use this identifier to cite or link to this item:
https://hdl.handle.net/10316/7857
Title: | Ca2+ Sensitivity of Synaptic Vesicle Dopamine, ?-Aminobutyric Acid, and Glutamate Transport Systems | Authors: | Gonçalves, Paula P. Meireles, Sandra M. Neves, Paulo Vale, M. Graça P. |
Issue Date: | 2001 | Citation: | Neurochemical Research. 26:1 (2001) 75-81 | Abstract: | The effect of Ca2+ on the uptake of neurotransmitters by synaptic vesicles was investigated in a synaptic vesicle enriched fraction isolated from sheep brain cortex. We observed that dopamine uptake, which is driven at expenses of the proton concentration gradient generated across the membrane by the H+-ATPase activity, is strongly inhibited (70%) by 500 µM Ca2+. Conversely, glutamate uptake, which essentially requires the electrical potential in the presence of low Cl- concentrations, is not affected by Ca2+, even when the proton concentration gradient greatly contributes for the proton electrochemical gradient. These observations were checked by adding Ca2+ to dopamine or glutamate loaded vesicles, which promoted dopamine release, whereas glutamate remained inside the vesicles. Furthermore, similar effects were obtained by adding 150 µM Zn2+ that, like Ca2+, dissipates the proton concentration gradient by exchanging with H+. With respect to ?-aminobutyric acid transport, which utilizes either the proton concentration gradient or the electrical potential as energy sources, we observed that Ca2+ or Zn2+ do not induce great alterations in the ?-aminobutyric acid accumulation by synaptic vesicles. These results clarify the nature of the energy source for accumulation of main neurotransmitters and suggest that stressing concentrations of Ca2+ or Zn2+ inhibit the proton concentration gradient-dependent neurotransmitter accumulation by inducing H+ pump uncoupling rather than by interacting with the neurotransmitter transporter molecules. | URI: | https://hdl.handle.net/10316/7857 | DOI: | 10.1023/A:1007684716964 | Rights: | openAccess |
Appears in Collections: | FCTUC Ciências da Vida - Artigos em Revistas Internacionais |
Show full item record
SCOPUSTM
Citations
7
checked on May 1, 2023
WEB OF SCIENCETM
Citations
10
7
checked on Sep 2, 2024
Page view(s) 20
811
checked on Sep 24, 2024
Download(s) 5
6,592
checked on Sep 24, 2024
Google ScholarTM
Check
Altmetric
Altmetric
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.