Background: We have previously demonstrated that the metabotropic glutamate 2 and 3 (mGlu) antagonist LY341495 reverses the anti-dyskinetic and anti-psychotic benefits conferred by mGlu activation and serotonin 2A (5-HT) antagonism. Here, we hypothesised that a higher dose of LY341495, associated with a higher antagonistic effect at mGlu receptors, would result in a reduction of the reversal of mGlu activation and 5-HT blockade on dyskinesia, in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned marmoset.
Methods: After induction of parkinsonism with MPTP, marmosets entered 3 streams of experiments, in which the following treatments were administered, in combination with l-3,4-dihydroxyphenylalanine (L-DOPA), after which dyskinesia, psychosis-like behaviours (PLBs) and parkinsonism were rated: 1. vehicle/vehicle, LY354740 (mGlu orthosteric agonist)/vehicle, LY354740/LY341495 1 mg/kg and LY354740/LY341495 3 mg/kg; 2. vehicle/vehicle, LY487379 (mGlu positive allosteric modulator)/vehicle, LY487379/LY341495 1 mg/kg and LY487379/LY341495 3 mg/kg; 3. vehicle/vehicle, EMD-281,014 (5-HT antagonist)/vehicle, EMD-281,014/LY341495 1 mg/kg and EMD-281,014/LY341495 3 mg/kg.
Results: Each of LY354740, LY487379 and EMD-281,014 reduced the severity of L-DOPA-induced dyskinesia, by 55%, 39% and 40%, respectively (all p < 0.001), as well as the severity of PLBs, by 48%, 36% and 41%, respectively (all p < 0.001). Adding LY341495 1 and 3 mg/kg to each of LY354740, LY487379 and EMD-281,014 resulted in a dose-dependent reversal of their anti-dyskinetic and anti-psychotic actions. No effect on the anti-parkinsonian action of L-DOPA was noted with any treatment combination.
Conclusion: These results suggest that an antagonistic effect at mGlu receptors may not be sufficient to overcome the deleterious effect of mGlu blockade on dyskinesia in PD. It remains to be seen whether similar effects would have been obtained with a selective mGlu antagonist.
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http://dx.doi.org/10.1007/s43440-022-00378-9 | DOI Listing |
ACS Pharmacol Transl Sci
December 2024
Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, VIC 3052, Australia.
Metabotropic glutamate receptors are a family of eight class C G protein-coupled receptors regulating higher order brain functions including cognition and motion. Metabotropic glutamate receptors have thus been heavily investigated as potential drug targets for treating neurological disorders. Drug discovery efforts directed toward metabotropic glutamate receptor subtype 5 (mGlu) have been particularly fruitful, with a wealth of drug candidates and pharmacological tools identified.
View Article and Find Full Text PDFNat Commun
November 2024
Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, China.
Talanta
August 2024
Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, China. Electronic address:
The expression of metabotropic glutamate receptor 5 (mGluR5) is subject to developmental regulation and undergoes significant changes in neuropsychiatric disorders and diseases. Visualizing mGluR5 by fluorescence imaging is a highly desired innovative technology for biomedical applications. Nevertheless, there are substantial problems with the chemical probes that are presently accessible.
View Article and Find Full Text PDFJ Med Chem
July 2024
Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, Université Paris Cité, CNRS UMR 8601, 75006 Paris, France.
Metabotropic glutamate (mGlu) receptors play a key role in modulating most synapses in the brain. The mGlu7 receptors inhibit presynaptic neurotransmitter release and offer therapeutic possibilities for post-traumatic stress disorders or epilepsy. Screening campaigns provided mGlu7-specific allosteric modulators as the inhibitor (Gee et al.
View Article and Find Full Text PDFPharmacol Rep
June 2024
Department of Medicinal Chemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna Street, Kraków, 31-343, Poland.
Background: Partial negative allosteric modulators (NAM) of the metabotropic glutamate 5 (mGlu) receptor are an excellent alternative to full antagonists and NAMs because they retain therapeutic effects and have a much broader therapeutic window. Here, we investigated whether partial mGlu NAM, 2-(2-(3-methoxyphenyl)ethynyl)-5-methylpyridine (M-5MPEP), induced a fast and sustained antidepressant-like effect, characteristic of rapid-acting antidepressant drugs (RAADs) like ketamine, in mice.
Methods: A tail suspension test (TST) was used to investigate acute antidepressant-like effects.
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