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Effect of the mGlu4 positive allosteric modulator ADX-88178 on parkinsonism, psychosis-like behaviours and dyskinesia in the MPTP-lesioned marmoset.
- Source :
- Psychopharmacology; Oct2023, Vol. 240 Issue 10, p2093-2099, 7p, 3 Graphs
- Publication Year :
- 2023
-
Abstract
- Rationale: Positive allosteric modulation of metabotropic glutamate type 4 (mGlu<subscript>4</subscript>) receptors is a promising strategy to alleviate parkinsonian disability and L-3,4-dihydroxyphenylalanine (L-DOPA) induced dyskinesia. ADX-88178 is a highly selective mGlu<subscript>4</subscript> positive allosteric modulator (PAM) that previously enhanced the anti-parkinsonian action of L-DOPA in the 6-hydroxydopamine-lesioned rat model of Parkinson's disease (PD). Objectives: We sought to explore the effects of ADX-88178 on psychosis-like behaviours (PLBs) in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned marmoset. We also aimed to determine the effect of ADX-88178 on parkinsonism and dyskinesia. Methods: Six MPTP-lesioned marmosets were administered L-DOPA chronically to induce stable PLBs and dyskinesias. They were then administered ADX-88178 (0.01, 0.1 and 1 mg/kg) or vehicle, in combination with L-DOPA/benserazide (15/3.75 mg/kg), both sub-cutaneously, in a randomised fashion. PLBs, parkinsonism and dyskinesia were then measured. Results: ADX-88178 mildly worsened global PLBs at the dose of 1 mg/kg (by 13%, P = 0.020). L-DOPA alone conferred 158 min of on-time, while the duration of on-time was 212 min (34% increase, P = 0.011), after adding ADX-88178 1 mg/kg to L-DOPA. Accordingly, ADX-88178 1 mg/kg reduced global parkinsonian disability, by 38% (P = 0.0096). ADX-88178 1 mg/kg diminished peak dose dyskinesia by 34% (P = 0.015). Minimal effects were provided by lower doses. Conclusions: Whereas these results provide additional evidence of the anti-parkinsonian and anti-dyskinetic effects of mGlu<subscript>4</subscript> positive allosteric modulation as an adjunct to L-DOPA, they also suggest that ADX-88178 may exacerbate dopaminergic psychosis. Further studies are needed to evaluate this possible adverse effect of mGlu<subscript>4</subscript> PAMs on PD psychosis. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00333158
- Volume :
- 240
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- Psychopharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 171993170
- Full Text :
- https://doi.org/10.1007/s00213-023-06428-1