Valine but not leucine or isoleucine supports neurotransmitter glutamate synthesis during synaptic activity in cultured cerebellar neurons
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Valine but not leucine or isoleucine supports neurotransmitter glutamate synthesis during synaptic activity in cultured cerebellar neurons. / Bak, Lasse Kristoffer; Johansen, Maja L.; Schousboe, Arne; Waagepetersen, Helle S.
In: Journal of Neuroscience Research, Vol. 90, No. 9, 2012, p. 1768-75.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Valine but not leucine or isoleucine supports neurotransmitter glutamate synthesis during synaptic activity in cultured cerebellar neurons
AU - Bak, Lasse Kristoffer
AU - Johansen, Maja L.
AU - Schousboe, Arne
AU - Waagepetersen, Helle S
N1 - Copyright © 2012 Wiley Periodicals, Inc.
PY - 2012
Y1 - 2012
N2 - Synthesis of neuronal glutamate from a-ketoglutarate for neurotransmission necessitates an amino group nitrogen donor; however, it is not clear which amino acid(s) serves this role. Thus, the ability of the three branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, to act as amino group nitrogen donors for synthesis of vesicular neurotransmitter glutamate was investigated in cultured mouse cerebellar (primarily glutamatergic) neurons. The cultures were superfused in the presence of (15) N-labeled BCAAs, and synaptic activity was induced by pulses of N-methyl-D-aspartate (300 µM), which results in release of vesicular glutamate. At the end of the superfusion experiment, the vesicular pool of glutamate was released by treatment with a-latrotoxin (3 nM, 5 min). This experimental paradigm allows a separate analysis of the cytoplasmic and vesicular pools of glutamate. Amount and extent of (15) N labeling of intracellular amino acids plus vesicular glutamate were analyzed employing HPLC and LC-MS analysis. Only when [(15) N]valine served as precursor did the labeling of both cytoplasmic and vesicular glutamate increase after synaptic activity. In addition, only [(15) N]valine was able to maintain the amount of vesicular glutamate during synaptic activity. This indicates that, among the BCAAs, only valine supports the increased need for synthesis of vesicular glutamate. © 2012 Wiley Periodicals, Inc.
AB - Synthesis of neuronal glutamate from a-ketoglutarate for neurotransmission necessitates an amino group nitrogen donor; however, it is not clear which amino acid(s) serves this role. Thus, the ability of the three branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, to act as amino group nitrogen donors for synthesis of vesicular neurotransmitter glutamate was investigated in cultured mouse cerebellar (primarily glutamatergic) neurons. The cultures were superfused in the presence of (15) N-labeled BCAAs, and synaptic activity was induced by pulses of N-methyl-D-aspartate (300 µM), which results in release of vesicular glutamate. At the end of the superfusion experiment, the vesicular pool of glutamate was released by treatment with a-latrotoxin (3 nM, 5 min). This experimental paradigm allows a separate analysis of the cytoplasmic and vesicular pools of glutamate. Amount and extent of (15) N labeling of intracellular amino acids plus vesicular glutamate were analyzed employing HPLC and LC-MS analysis. Only when [(15) N]valine served as precursor did the labeling of both cytoplasmic and vesicular glutamate increase after synaptic activity. In addition, only [(15) N]valine was able to maintain the amount of vesicular glutamate during synaptic activity. This indicates that, among the BCAAs, only valine supports the increased need for synthesis of vesicular glutamate. © 2012 Wiley Periodicals, Inc.
U2 - 10.1002/jnr.23072
DO - 10.1002/jnr.23072
M3 - Journal article
C2 - 22589238
VL - 90
SP - 1768
EP - 1775
JO - Journal of Neuroscience Research
JF - Journal of Neuroscience Research
SN - 0360-4012
IS - 9
ER -
ID: 38463340