Layer-specific potentiation of network GABAergic inhibition in the CA1 area of the hippocampus.

Michelangelo Colavita, Geoffrey Terral, Clement E. Lemercier, Filippo Drago, Giovanni Marsicano, Federico Massa
Sci Rep. 2016-06-27; 6(1):
DOI: 10.1038/srep28454

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1. Sci Rep. 2016 Jun 27;6:28454. doi: 10.1038/srep28454.

Layer-specific potentiation of network GABAergic inhibition in the CA1 area of
the hippocampus.

Colavita M(1)(2)(3), Terral G(1)(2), Lemercier CE(1)(2), Drago F(3), Marsicano
G(1)(2), Massa F(1)(2).

Author information:
(1)INSERM U1215, NeuroCentre Magendie, AVENIR Group “Endocannabinoids and
Neuroadaptation”, 33077 Bordeaux, France.
(2)Université de Bordeaux, 33077 Bordeaux, France.
(3)University of Catania, Biometec – Department of Biomedical and
Biotechnological Sciences, 95125 Catania, Italy.

One of the most important functions of GABAergic inhibition in cortical regions
is the tight control of spatiotemporal activity of principal neuronal ensembles.
However, electrophysiological recordings do not provide sufficient spatial
information to determine the spatiotemporal properties of inhibitory plasticity.
Using Voltage Sensitive Dye Imaging (VSDI) in mouse hippocampal slices, we
demonstrate that GABAA-mediated field inhibitory postsynaptic potentials undergo
layer-specific potentiation upon activation of metabotropic glutamate receptors
(mGlu). VSDI recordings allowed detection of pharmacologically isolated
GABAA-dependent hyperpolarization signals. Bath-application of the selective
group-I mGlu receptor agonist, (S)-3,5-Dihydroxyphenylglycine (DHPG), induces an
enhancement of the GABAergic VSDI-recorded signal, which is more or less
pronounced in different hippocampal layers. This potentiation is mediated by
mGlu5 and downstream activation of IP3 receptors. Our results depict network
GABAergic activity in the hippocampal CA1 region and its sub-layers, showing also
a novel form of inhibitory synaptic plasticity tightly coupled to glutamatergic

DOI: 10.1038/srep28454
PMCID: PMC4921906
PMID: 27345695 [Indexed for MEDLINE]

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