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

A. Kerr, E. Reisinger, P.M. Jonas, PNAS 105 (2008) 15581–6.

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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, 105(40), 15581–15586. 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 105, no. 40 (2008): 15581–86. 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, 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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