Non-neuronal, slow GABA signalling in the ventrobasal thalamus targets δ-subunit-containing GABA(A) receptors


The rodent ventrobasal (VB) thalamus contains a relatively uniform population of thalamocortical (TC) neurons that receive glutamatergic input from the vibrissae and the somatosensory cortex, and inhibitory input from the nucleus reticularis thalami (nRT). In this study we describe ?-aminobutyric acid (GABA)(A) receptor-dependent slow outward currents (SOCs) in TC neurons that are distinct from fast inhibitory postsynaptic currents (IPSCs) and tonic currents. SOCs occurred spontaneously or could be evoked by hypo-osmotic stimulus, and were not blocked by tetrodotoxin, removal of extracellular Ca(2+) or bafilomycin A1, indicating a non-synaptic, non-vesicular GABA origin. SOCs were more common in TC neurons of the VB compared with the dorsal lateral geniculate nucleus, and were rarely observed in nRT neurons, whilst SOC frequency in the VB increased with age. Application of THIP, a selective agonist at d-subunit-containing GABA(A) receptors, occluded SOCs, whereas the benzodiazepine site inverse agonist ß-CCB had no effect, but did inhibit spontaneous and evoked IPSCs. In addition, the occurrence of SOCs was reduced in mice lacking the d-subunit, and their kinetics were also altered. The anti-epileptic drug vigabatrin increased SOC frequency in a time-dependent manner, but this effect was not due to reversal of GABA transporters. Together, these data indicate that SOCs in TC neurons arise from astrocytic GABA release, and are mediated by d-subunit-containing GABA(A) receptors. Furthermore, these findings suggest that the therapeutic action of vigabatrin may occur through the augmentation of this astrocyte-neuron interaction, and highlight the importance of glial cells in CNS (patho) physiology.

Publication DOI:
Divisions: College of Health & Life Sciences
College of Health & Life Sciences > Clinical and Systems Neuroscience
College of Health & Life Sciences > Aston Pharmacy School
Additional Information: © 2011 The Authors. European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.
Uncontrolled Keywords: animals,astrocytes,female,GABA agents,male,mice,knockout mice,neurons,patch-clamp techniques,rats,Wistar rats,GABA-A receptors,signal transduction,thalamus,vigabatrin,gamma-aminobutyric acid,General Neuroscience
Publication ISSN: 1460-9568
Last Modified: 17 Jul 2024 07:03
Date Deposited: 11 Jul 2012 09:36
Full Text Link: http://onlineli ... 7645.x/abstract
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2011-04
Published Online Date: 2011-03-13
Authors: Jiménez-González, Cristina
Pirttimaki, Tiina
Cope, David W.
Parri, H. Rheinallt (ORCID Profile 0000-0002-1412-2688)



Version: Accepted Version

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