Articles

  • the Korean Society for Brain and Neural Sciences

Article

Original Article

Exp Neurobiol 2015; 24(3): 211-218

Published online September 30, 2015

https://doi.org/10.5607/en.2015.24.3.211

© The Korean Society for Brain and Neural Sciences

Disinhibitory Action of Astrocytic GABA at the Perforant Path to Dentate Gyrus Granule Neuron Synapse Reverses to Inhibitory in Alzheimer's Disease Model

Oleg Yarishkin1, Jaekwang Lee1, Seonmi Jo1,2, Eun Mi Hwang1,3 and C. Justin Lee1,3,4*

1Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, 2Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, 3Neuroscience Program, University of Science and Technology (UST), Daejeon 34113, 4KU-KIST Graduate School of Converging Science and Technology, Seoul 02841, Korea

Correspondence to: *To whom correspondence should be addressed.
TEL: 82-2-958-6940, FAX: 82-2-958-6937
e-mail: cjl@kist.re.kr

Received: June 30, 2015; Revised: August 25, 2015; Accepted: August 25, 2015

Abstract

Like neurons, astrocytes produce and release GABA to influence neuronal signaling. At the perforant path to dentate gyrus granule neuron synapse, GABA from astrocyte was found to be a strong inhibitory factor, which impairs synaptic transmission, synaptic plasticity and memory in Alzheimer's disease. Although astrocytic GABA is observed in many brain regions, its physiological role has not been clearly demonstrated yet. Here, we show that astrocytic GABA exerts disinhibitory action to dentate granule neurons by targeting GABAB receptors of GABAergic interneurons in wild-type mice. This disinhibitory effect is specific to a low intensity of electrical stimulation at perforant path fibers. Inversely in Alzheimer's disease model mice, astrocytic GABA targets GABAA receptors and exerts inhibitory action by reducing release probability of glutamatergic perforant path terminals. These results suggest that astrocytic GABA differentially modulates the signaling from cortical input to dentate gyrus under physiological and pathological conditions.

Keywords: Alzheimer’s disease, Astrocyte, Dentate gyrus, GABA, Perforant path