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Rapid ATP loss caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in mouse brain
P Chan1, L E DeLanney, I Irwin
1California Institute for Medical Research, San Jose 95128.
Abstract:
The effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on ATP levels in different areas of mouse brain were studied after rapid fixation of cerebral tissue in situ by microwave irradiation. ATP levels in the striatum, ventral mesencephalon, and cerebellum of untreated C57BL/6 mice killed by microwave irradiation were 2-3 times greater than values measured in the brains of animals killed by cervical dislocation. In microwaved mice, administration of MPTP (40 mg/kg s.c.) caused a 10-20% decrease in ATP concentrations as compared to control animals injected with saline. This decrease was relatively rapid and selective because it occurred in both the striatum and ventral mesencephalon, but not in the cerebellar and frontal cortex, at 30, 60, 120, and 240 min after MPTP exposure. Furthermore, ATP loss in the striatum was prevented by mazindol, a catecholamine uptake blocker, indicating a rather selective effect of MPTP on the ATP content of dopaminergic terminals. Results of this study are consistent with mitochondrial damage in the MPTP model of parkinsonism and provide the first direct experimental evidence in vivo that a decrease in ATP may play a role in MPTP-induced neurotoxicity.
Insights
1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes a rapid, selective decrease in brain ATP levels, particularly in dopaminergic terminals. This finding suggests reduced ATP plays a role in MPTP-induced parkinsonism neurotoxicity.
Area of Science:
- Neuroscience
- Biochemistry
- Toxicology
Background:
- 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin used to model Parkinson's disease.
- Adenosine triphosphate (ATP) is crucial for neuronal function and energy metabolism.
Purpose of the Study:
- To investigate the effects of MPTP on ATP levels in specific mouse brain regions.
- To determine if MPTP-induced ATP depletion is linked to dopaminergic neurotoxicity.
Main Methods:
- Cerebral tissue was rapidly fixed using microwave irradiation to preserve endogenous ATP levels.
- ATP concentrations were measured in the striatum, ventral mesencephalon, and cerebellum after MPTP administration.
- The effect of mazindol, a catecholamine uptake blocker, on MPTP-induced ATP changes was assessed.
Main Results:
- Microwave irradiation yielded significantly higher brain ATP levels compared to cervical dislocation.
- MPTP administration caused a 10-20% decrease in ATP levels in the striatum and ventral mesencephalon, but not the cerebellum or frontal cortex.
- Mazindol prevented ATP loss in the striatum, suggesting MPTP affects dopaminergic terminals.
Conclusions:
- MPTP induces a rapid and selective reduction in brain ATP, particularly in dopaminergic areas.
- The findings support the hypothesis of mitochondrial dysfunction in MPTP neurotoxicity.
- This study provides in vivo evidence that decreased ATP levels contribute to MPTP-induced neurotoxicity.