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Mechanisms of Supralinear Calcium Integration in Dendrites of Hippocampal CA1 Fast-Spiking Cells.
- Source :
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Frontiers in synaptic neuroscience [Front Synaptic Neurosci] 2018 Dec 11; Vol. 10, pp. 47. Date of Electronic Publication: 2018 Dec 11 (Print Publication: 2018). - Publication Year :
- 2018
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Abstract
- In fast-spiking (FS), parvalbumin-expressing interneurons of the CA1 hippocampus, activation of the GluA2-lacking Ca <superscript>2+</superscript> -permeable AMPA receptors (CP-AMPARs) in basal dendrites is coupled to Ca <superscript>2+</superscript> -induced Ca <superscript>2+</superscript> -release (CICR), and can result in a supralinear summation of postsynaptic Ca <superscript>2+</superscript> -transients (post-CaTs). While this mechanism is important in controlling the direction of long-term plasticity, it is still unknown whether it can operate at all excitatory synapses converging onto FS cells or at a set of synapses receiving a particular input. Using a combination of patch-clamp recordings and two-photon Ca <superscript>2+</superscript> imaging in acute mouse hippocampal slices with computational simulations, here we compared the generation of supralinear post-CaTs between apical and basal dendrites of FS cells. We found that, similar to basal dendrites, apical post-CaTs summated supralinearly and relied mainly on the activation of the CP-AMPARs, with a variable contribution of other Ca <superscript>2+</superscript> sources, such as NMDA receptors, L-type voltage-gated Ca <superscript>2+</superscript> -channels and Ca <superscript>2+</superscript> release. In addition, supralinear post-CaTs generated in apical dendrites had a slower decay time and a larger cumulative charge than those in basal, and were associated with a stronger level of somatic depolarization. The model predicted that modulation of ryanodine receptors and of the Ca <superscript>2+</superscript> extrusion mechanisms, such as the Na <superscript>+</superscript> /Ca <superscript>2+</superscript> -exchanger and SERCA pump, had a major impact on the magnitude of supralinear post-CaTs. These data reveal that supralinear Ca <superscript>2+</superscript> summation is a common mechanism of Ca <superscript>2+</superscript> signaling at CP-AMPAR-containing synapses. Shaped in a location-specific manner through modulation of ryanodine receptors and Ca <superscript>2+</superscript> extrusion mechanisms, CP-AMPAR/CICR signaling is suitable for synapse-specific bidirectional modification of incoming inputs in the absence of active dendritic conductances.
Details
- Language :
- English
- ISSN :
- 1663-3563
- Volume :
- 10
- Database :
- MEDLINE
- Journal :
- Frontiers in synaptic neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 30618708
- Full Text :
- https://doi.org/10.3389/fnsyn.2018.00047