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Increased dopamine turnover in the putamen after MPTP treatment in common marmosets
M Nomoto1, S I Iwata, S Kaseda
1Department of Pharmacology, Kagoshima University School of Medicine, Sakuragaoka, Japan.
Abstract:
The differences in dopamine turnover rate between the putamen and the caudate nucleus in the striatum lesioned by a neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were studied in the common marmoset, a small New World monkey. Systemic administration of MPTP damaged equally and dose-dependently nigrostriatal dopaminergic neurons projecting both to the caudate nucleus and the putamen. The compensatory increase of dopamine turnover, however, occurred more prominently in the putamen than in the caudate. The neural connection and function of the caudate nucleus and the putamen have been differentiated anatomically or physiologically. The compensatory increase of dopamine turnover rate is another different aspect of functions between the caudate nucleus and the putamen. Dopaminergic neurons projecting to the putamen showed more prominent cell loss than those projecting to the caudate in Parkinson's disease or related disorders. The selective augmented turnover rate of lesioned dopaminergic neurons might be, at least partly, involved with selective degeneration of nigrostriatal neurons projecting to the putamen.
Insights
MPTP neurotoxin caused dopamine neuron damage in marmosets. The putamen showed a stronger compensatory dopamine turnover increase than the caudate nucleus, suggesting functional differences.
Area of Science:
- Neuroscience
- Primate Research
- Neurotoxicology
Background:
- The striatum, comprising the caudate nucleus and putamen, plays a crucial role in motor control.
- Dopaminergic pathways are vital for striatal function, and their degeneration is implicated in Parkinson's disease.
- Previous research suggests functional and anatomical differences between the caudate nucleus and putamen.
Purpose of the Study:
- To investigate the differential response of dopamine turnover in the caudate nucleus and putamen following neurotoxin-induced striatal lesions.
- To explore functional distinctions between the caudate nucleus and putamen in the context of dopaminergic neurodegeneration.
Main Methods:
- Systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to common marmosets.
- Assessment of nigrostriatal dopaminergic neuron integrity and dopamine turnover rates in the caudate nucleus and putamen.
- Dose-dependent analysis of MPTP effects.
Main Results:
- MPTP caused equal, dose-dependent damage to nigrostriatal dopaminergic neurons projecting to both the caudate nucleus and putamen.
- A more prominent compensatory increase in dopamine turnover was observed in the putamen compared to the caudate nucleus.
- These findings highlight differential functional adaptations between the two striatal subregions.
Conclusions:
- The putamen exhibits a more pronounced compensatory response in dopamine turnover following MPTP-induced neurodegeneration than the caudate nucleus.
- This differential response underscores functional specialization between the caudate nucleus and putamen.
- The selective augmentation of dopamine turnover in lesioned neurons may be linked to the selective degeneration observed in nigrostriatal neurons projecting to the putamen in Parkinson's disease.