Glutamatergic input-output properties of thalamic astrocytes

Pirttimaki, Tiina M. and Parri, H. Rheinallt Glutamatergic input-output properties of thalamic astrocytes. Neuroscience, 205 , pp. 18-28.

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.

Publication DOI: https://doi.org/10.1016/j.neuroscience.2011.12.049
Divisions: Life & Health Sciences
Life & Health Sciences > Neurosciences research group
Life & Health Sciences > Pharmacy
Life & Health Sciences > Applied Health Research Group
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Additional Information: 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
Uncontrolled Keywords: astrocytes,glutamate,SIC,gliotransmission,somatosensory,tripartite synapse,Neuroscience(all)

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