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Mutual activation of glutamatergic mGlu4 and muscarinic M4 receptors reverses schizophrenia-related changes in rodents
Rationale Metabotropic glutamate receptors and muscarinic M 4 receptors have been proposed as novel targets for various brain disorders, including schizophrenia. Both receptors are coupled to G o/i proteins and are expressed in brain circuits that are important in schizophrenia. Therefore, their mut...
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Published in: | Psychopharmacology 2018-10, Vol.235 (10), p.2897-2913 |
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Main Authors: | , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Rationale
Metabotropic glutamate receptors and muscarinic M
4
receptors have been proposed as novel targets for various brain disorders, including schizophrenia. Both receptors are coupled to G
o/i
proteins and are expressed in brain circuits that are important in schizophrenia. Therefore, their mutual activation may be an effective treatment and allow minimizing the doses of ligands required for optimal activity.
Objectives
In the present studies, subactive doses of mGlu
4
and M
4
activators (LSP4-2022 and VU152100, respectively) were administered to investigate the mutual interaction between mGlu
4
and M
4
receptors in animal models of schizophrenia.
Methods
The behavioral tests used were MK-801-induced hyperactivity, (±)-2.5-dimethoxy-4-iodoamphetamine hydrochloride (DOI)-induced head twitches, the modified forced swim test, and MK-801-induced disruptions of social interactions and novel object recognition. DOI-induced spontaneous excitatory postsynaptic currents (sEPSCs) in brain slices and positron emission tomography (PET) in were used to establish the ability of these compounds to modulate the glutamatergic and dopaminergic systems. Rotarod was used to assess putative adverse effects.
Results
The mutual administration of subactive doses of LSP4-2022 and VU152100 exerted similar antipsychotic-like efficacy in animals as observed for active doses of both compounds, indicating their additive actions. VU152100 inhibited the DOI-induced frequency (but not amplitude) of sEPSCs in the frontal cortex, confirming presynaptic regulation of glutamate release. Both compounds reversed amphetamine-induced decrease in D
2
receptor levels in the striatum, as measured with [
18
F]fallypride. The compounds did not induce any motor impartments when measured in rotarod test.
Conclusions
Based on our results, the simultaneous activation of M
4
and mGlu
4
receptors is beneficial in reversing MK-801- and amphetamine-induced schizophrenia-related changes in animals. |
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ISSN: | 0033-3158 1432-2072 |
DOI: | 10.1007/s00213-018-4980-y |