Differential dependence of phasic transmitter release on synaptotagmin 1 at GABAergic and glutamatergic hippocampal synapses

Kerr A, Reisinger E, Jonas PM. 2008. Differential dependence of phasic transmitter release on synaptotagmin 1 at GABAergic and glutamatergic hippocampal synapses. PNAS. 105(40), 15581–6.

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Author
Kerr, Angharad M; Reisinger, Ellen; Jonas, Peter MIST Austria
Abstract
Previous studies revealed that synaptotagmin 1 is the major Ca(2+) sensor for fast synchronous transmitter release at excitatory synapses. However, the molecular identity of the Ca(2+) sensor at hippocampal inhibitory synapses has not been determined. To address the functional role of synaptotagmin 1 at identified inhibitory terminals, we made paired recordings from synaptically connected basket cells (BCs) and granule cells (GCs) in the dentate gyrus in organotypic slice cultures from wild-type and synaptotagmin 1-deficient mice. As expected, genetic elimination of synaptotagmin 1 abolished synchronous transmitter release at excitatory GC-BC synapses. However, synchronous release at inhibitory BC-GC synapses was maintained. Quantitative analysis revealed that elimination of synaptotagmin 1 reduced release probability and depression but maintained the synchrony of transmitter release at BC-GC synapses. Elimination of synaptotagmin 1 also increased the frequency of both miniature excitatory postsynaptic currents (measured in BCs) and miniature inhibitory postsynaptic currents (recorded in GCs), consistent with a clamping function of synaptotagmin 1 at both excitatory and inhibitory terminals. Single-cell reverse-transcription quantitative PCR analysis revealed that single BCs coexpressed multiple synaptotagmin isoforms, including synaptotagmin 1-5, 7, and 11-13. Our results indicate that, in contrast to excitatory synapses, synaptotagmin 1 is not absolutely required for synchronous release at inhibitory BC-GC synapses. Thus, alternative fast Ca(2+) sensors contribute to synchronous release of the inhibitory transmitter GABA in cortical circuits.
Publishing Year
Date Published
2008-01-01
Journal Title
PNAS
Volume
105
Issue
40
Page
15581 - 6
IST-REx-ID

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Kerr A, Reisinger E, Jonas PM. Differential dependence of phasic transmitter release on synaptotagmin 1 at GABAergic and glutamatergic hippocampal synapses. PNAS. 2008;105(40):15581-15586. doi:10.1073/pnas.0800621105
Kerr, A., Reisinger, E., & Jonas, P. M. (2008). Differential dependence of phasic transmitter release on synaptotagmin 1 at GABAergic and glutamatergic hippocampal synapses. PNAS. National Academy of Sciences. https://doi.org/10.1073/pnas.0800621105
Kerr, Angharad, Ellen Reisinger, and Peter M Jonas. “Differential Dependence of Phasic Transmitter Release on Synaptotagmin 1 at GABAergic and Glutamatergic Hippocampal Synapses.” PNAS. National Academy of Sciences, 2008. https://doi.org/10.1073/pnas.0800621105.
A. Kerr, E. Reisinger, and P. M. Jonas, “Differential dependence of phasic transmitter release on synaptotagmin 1 at GABAergic and glutamatergic hippocampal synapses,” PNAS, vol. 105, no. 40. National Academy of Sciences, pp. 15581–6, 2008.
Kerr A, Reisinger E, Jonas PM. 2008. Differential dependence of phasic transmitter release on synaptotagmin 1 at GABAergic and glutamatergic hippocampal synapses. PNAS. 105(40), 15581–6.
Kerr, Angharad, et al. “Differential Dependence of Phasic Transmitter Release on Synaptotagmin 1 at GABAergic and Glutamatergic Hippocampal Synapses.” PNAS, vol. 105, no. 40, National Academy of Sciences, 2008, pp. 15581–86, doi:10.1073/pnas.0800621105.

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