Glutamatergic input-output properties of thalamic astrocytes

Tiina M. Pirttimaki, H. Rheinallt Parri

Research output: Contribution to journalArticle

Abstract

Astrocytes in the somatosensory ventrobasal (VB) thalamus of rats respond to glutamatergic synaptic input with metabotropic glutamate receptor (mGluR) mediated intracellular calcium ([Ca²?](i)) elevations. Astrocytes in the VB thalamus also release the gliotransmitter (GT) glutamate in a Ca²?-dependent manner. The tripartite synapse hypothesis posits that astrocytic [Ca²?](i) elevations resulting from synaptic input releases gliotransmitters that then feedback to modify the synapse. Understanding the dynamics of this process and the conditions under which it occurs are therefore important steps in elucidating the potential roles and impact of GT release in particular brain activities. In this study, we investigated the relationship between VB thalamus afferent synaptic input and astrocytic glutamate release by recording N-methyl-D-aspartate (NMDA) receptor-mediated slow inward currents (SICs) elicited in neighboring neurons. We found that Lemniscal or cortical afferent stimulation, which can elicit astrocytic [Ca²?](i) elevations, do not typically result in the generation of SICs in thalamocortical (TC) neurons. Rather, we find that the spontaneous emergence of SICs is largely resistant to acute afferent input. The frequency of SICs, however, is correlated to long-lasting afferent activity. In contrast to short-term stimulus-evoked GT release effects reported in other brain areas, astrocytes in the VB thalamus do not express a straightforward input-output relationship for SIC generation but exhibit integrative characteristics.
LanguageEnglish
Pages18-28
Number of pages11
JournalNeuroscience
Volume205
Early online date3 Jan 2012
DOIs
Publication statusPublished - 15 Mar 2012

Fingerprint

Thalamus
Astrocytes
Synapses
Glutamic Acid
Neurons
Metabotropic Glutamate Receptors
Brain
N-Methyl-D-Aspartate Receptors
Calcium

Bibliographical note

NOTICE: this is the author’s version of a work that was accepted for publication in Neuroscience. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Pirttimaki, TM & Parri, HR, 'Glutamatergic input-output properties of thalamic astrocytes', Neuroscience, vol. 205 (2012) DOI http://dx.doi.org/10.1016/j.neuroscience.2011.12.049

Keywords

  • astrocytes
  • glutamate
  • SIC
  • gliotransmission
  • somatosensory
  • tripartite synapse

Cite this

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Glutamatergic input-output properties of thalamic astrocytes. / Pirttimaki, Tiina M.; Parri, H. Rheinallt.

In: Neuroscience, Vol. 205, 15.03.2012, p. 18-28.

Research output: Contribution to journalArticle

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