Abstract
In monoamine-releasing terminals, neurotransmitter transporters - in addition to terminating synaptic transmission by clearing released transmitters from the extracellular space - are the primary mechanism for replenishing transmitter stores and thus regulate presynaptic homeostasis. Here, we analyze whether GAT-1, the main plasma membrane GABA transporter, plays a similar role in GABAergic terminals. Re-examination of existing literature and recent data gathered in our laboratory show that GABA homeostasis in GABAergic terminals is dominated by the activity of the GABA synthesizing enzyme and that GAT-1-mediated GABA transport contributes to cytosolic GABA levels. However, analysis of GAT-1 KO, besides demonstrating the effects of reduced clearance, reveals the existence of changes compatible with an impaired presynaptic function, as miniature IPSCs frequency is reduced by one-third and glutamic acid decarboxylases and phosphate-activated glutaminase levels are significantly up-regulated. Although the changes observed are less robust than those reported in mice with impaired dopamine, noradrenaline, and serotonin plasma membrane transporters, they suggest that in GABAergic terminals GAT-1 impacts on presynaptic GABA homeostasis, and may contribute to the activity-dependent regulation of inhibitory efficacy.
| Original language | English |
|---|---|
| Pages (from-to) | 10 |
| Number of pages | 1 |
| Journal | Frontiers in Cellular Neuroscience |
| Issue number | APRIL |
| DOIs | |
| Publication status | Published - Apr 5 2011 |
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Keywords
- GABA
- GABA transporters
- GAT-1
- Knock-out mice
- mIPSCS
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience
Cite this
A role for GAT-1 in presynaptic GABA homeostasis? / Conti, Fiorenzo; Melone, Marcello; Fattorini, Giorgia; Bragina, Luca; Ciappelloni, Silvia.
In: Frontiers in Cellular Neuroscience, No. APRIL, 05.04.2011, p. 10.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - A role for GAT-1 in presynaptic GABA homeostasis?
AU - Conti, Fiorenzo
AU - Melone, Marcello
AU - Fattorini, Giorgia
AU - Bragina, Luca
AU - Ciappelloni, Silvia
PY - 2011/4/5
Y1 - 2011/4/5
N2 - In monoamine-releasing terminals, neurotransmitter transporters - in addition to terminating synaptic transmission by clearing released transmitters from the extracellular space - are the primary mechanism for replenishing transmitter stores and thus regulate presynaptic homeostasis. Here, we analyze whether GAT-1, the main plasma membrane GABA transporter, plays a similar role in GABAergic terminals. Re-examination of existing literature and recent data gathered in our laboratory show that GABA homeostasis in GABAergic terminals is dominated by the activity of the GABA synthesizing enzyme and that GAT-1-mediated GABA transport contributes to cytosolic GABA levels. However, analysis of GAT-1 KO, besides demonstrating the effects of reduced clearance, reveals the existence of changes compatible with an impaired presynaptic function, as miniature IPSCs frequency is reduced by one-third and glutamic acid decarboxylases and phosphate-activated glutaminase levels are significantly up-regulated. Although the changes observed are less robust than those reported in mice with impaired dopamine, noradrenaline, and serotonin plasma membrane transporters, they suggest that in GABAergic terminals GAT-1 impacts on presynaptic GABA homeostasis, and may contribute to the activity-dependent regulation of inhibitory efficacy.
AB - In monoamine-releasing terminals, neurotransmitter transporters - in addition to terminating synaptic transmission by clearing released transmitters from the extracellular space - are the primary mechanism for replenishing transmitter stores and thus regulate presynaptic homeostasis. Here, we analyze whether GAT-1, the main plasma membrane GABA transporter, plays a similar role in GABAergic terminals. Re-examination of existing literature and recent data gathered in our laboratory show that GABA homeostasis in GABAergic terminals is dominated by the activity of the GABA synthesizing enzyme and that GAT-1-mediated GABA transport contributes to cytosolic GABA levels. However, analysis of GAT-1 KO, besides demonstrating the effects of reduced clearance, reveals the existence of changes compatible with an impaired presynaptic function, as miniature IPSCs frequency is reduced by one-third and glutamic acid decarboxylases and phosphate-activated glutaminase levels are significantly up-regulated. Although the changes observed are less robust than those reported in mice with impaired dopamine, noradrenaline, and serotonin plasma membrane transporters, they suggest that in GABAergic terminals GAT-1 impacts on presynaptic GABA homeostasis, and may contribute to the activity-dependent regulation of inhibitory efficacy.
KW - GABA
KW - GABA transporters
KW - GAT-1
KW - Knock-out mice
KW - mIPSCS
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UR - http://www.scopus.com/inward/citedby.url?scp=84862590669&partnerID=8YFLogxK
U2 - 10.3389/fncel.2011.00002
DO - 10.3389/fncel.2011.00002
M3 - Article
C2 - 21503156
AN - SCOPUS:84862590669
SP - 10
JO - Frontiers in Cellular Neuroscience
JF - Frontiers in Cellular Neuroscience
SN - 1662-5102
IS - APRIL
ER -