Probing the polarity of spontaneous perisomatic GABAergic synaptic transmission in the mouse CA3 circuit in vivo.

Dubanet O(1), Ferreira Gomes Da Silva A(2), Frick A(1), Hirase H(3), Beyeler A(1), Leinekugel X(4).

Author information:
(1)University of Bordeaux, INSERM U1215, Neurocentre Magendie, 33077 Bordeaux,
France.
(2)University of Bordeaux, INSERM U1215, Neurocentre Magendie, 33077 Bordeaux,
France; INMED, INSERM, Aix Marseille Univ, France.
(3)Center for Translational Neuromedicine, University of Copenhagen, Copenhagen,
Denmark.
(4)University of Bordeaux, INSERM U1215, Neurocentre Magendie, 33077 Bordeaux,
France; INMED, INSERM, Aix Marseille Univ, France. Electronic address:
.

The hypothesis that reversed, excitatory GABA may be involved in various brain
pathologies, including epileptogenesis, is appealing but controversial because of
the technical difficulty of probing endogenous GABAergic synaptic function
in vivo. We overcome this challenge by non-invasive extracellular recording of
neuronal firing responses to optogenetically evoked and spontaneously occurring
inhibitory perisomatic GABAergic field potentials, generated by individual
parvalbumin interneurons on their target pyramidal cells. Our direct probing of
GABAergic transmission suggests a rather anecdotal participation of excitatory
GABA in two specific models of epileptogenesis in the mouse CA3 circuit in vivo,
even though this does not preclude its expression in other brain areas or
pathological conditions. Our approach allows the detection of distinct
alterations of inhibition during spontaneous activity in vivo, with high
sensitivity. It represents a promising tool for the investigation of excitatory
GABA in different pathological conditions that may affect the hippocampal
circuit.

Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.

Auteurs Bordeaux Neurocampus