Group II metabotropic glutamate receptor (mGlu2 and mGlu3) roles in thalamic processing. (15th September 2021)

• Record Type: Journal Article
• Authors: Copeland, Caroline S.; Neale, Stuart A.; Nisenbaum, Eric S.; Salt, Thomas E.
• Other Names: Camarini Rosana guestEditor.; Scavone Cristoforo guestEditor.; Berwick Daniel guestEditor.; Bailey Alexis guestEditor.
• Is Part Of: British journal of pharmacology. Volume 179:Number 8(2022)
• Page Start: 1607
• Page End: 1619
• Publication Date: 2021-09-15
• Subjects: electrophysiology -- metabotropic glutamate receptors -- schizophrenia -- sensory processing -- thalamic reticular nucleus -- ventrobasal thalamus; Pharmacology -- Periodicals; Chemotherapy -- Periodicals; Drug Therapy -- Periodicals; Pharmacology -- Periodicals; 615.1
• DOI: 10.1111/bph.15640
• Languages: English
• ISSNs: 0007-1188

Abstract

Abstract : Background and Purpose: As the thalamus underpins almost all aspects of behaviour, it is important to understand how the thalamus operates. Group II metabotropic glutamate (mGlu2 /mGlu3 ) receptor activation reduces inhibition in thalamic nuclei originating from the surrounding thalamic reticular nucleus (TRN). Whilst an mGlu2 component to this effect has been reported, in this study, we demonstrate that it is likely, largely mediated via mGlu3 . Experimental Approach: The somatosensory ventrobasal thalamus (VB) is an established model for probing fundamental principles of thalamic function. In vitro slices conserving VB–TRN circuitry from wild‐type and mGlu3 knockout mouse brains were used to record IPSPs and mIPSCs. In vivo extracellular recordings were made from VB neurons in anaesthetised rats. A range of selective pharmacological agents were used to probe Group II mGlu receptor function (agonist, LY354740; antagonist, LY341495; mGlu2 positive allosteric modulator, LY487379 and mixed mGlu2 agonist/mGlu3 antagonist LY395756). Key Results: The in vitro and in vivo data are complementary and suggest that mGlu3 receptor activation is largely responsible for potentiating responses to somatosensory stimulation by reducing inhibition from the TRN. Conclusions and Implications: mGlu3 receptor activation in the VB likely enables important somatosensory information to be discerned from background activity. These mGlu3 receptors are likely to be endogenously activated via 'glutamate spillover'. In cognitive thalamic nuclei, this mechanism may be of importance in governing attentional processes. Positive allosteric modulation of endogenous mGlu3 receptor activation may therefore enhance cognitive function in pathophysiological disease states, such as schizophrenia, thus representing a highly specific therapeutic target. LINKED ARTICLES: This article is part of a themed issue on Building Bridges in Neuropharmacology. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.8/issuetoc