Abstract
Cortical GABAergic synapses exhibit a high degree of molecular, anatomical and functional heterogeneity of their neurons of origins, presynaptic mechanisms, receptors, and scaffolding proteins. GABA transporters (GATs) have an important role in regulating GABA levels; among them, GAT-1 and GAT-3 play a prominent role in modulating tonic and phasic GABAAR-mediated inhibition. We asked whether GAT-1 and GAT-3 contribute to generating heterogeneity by studying their ultrastructural localization at cortical symmetric synapses using pre-and post-embedding electron microcopy. GAT-1 and GAT-3 staining at symmetric synapses showed that in some cases the transporters were localized exclusively over axon terminals; in others they were in both axon terminals and perisynaptic astrocytic processes; and in some others GAT-1 and GAT-3 were in perisynaptic astrocytic processes only. Moreover, we showed that the organizational pattern of GAT-1, but not of GAT-3, exhibits a certain degree of specificity related to the post-synaptic target of GABAergic synapses. These findings show that symmetric synapses expressing GAT-1 or GAT-3 are heterogeneous, and indicate that plasma membrane transporters can contribute to synaptic heterogeneity.
Original language | English |
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Article number | 72 |
Journal | Frontiers in Neuroanatomy |
Volume | 8 |
Issue number | JULY |
DOIs | |
Publication status | Published - Jul 25 2014 |
Keywords
- GABA
- GABA transporters
- GAT-1
- GAT-3
- Heterogeneity
- Symmetric synapses
ASJC Scopus subject areas
- Anatomy
- Neuroscience (miscellaneous)
- Cellular and Molecular Neuroscience