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1-Methyl-4-phenylpyridine (MPP+) induces oxidative stress in the rodent
Abstract:
MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) produces an irreversible parkinsonism in primates. Recent evidence suggests metabolism of MPTP to 1-methyl-4-phenylpyridine (MPP+) is required for toxicity. We have proposed that MPP+ may play a central role in the toxicity of MPTP, but direct assessment of the effects of MPP+ in brain is difficult. Therefore, we have sought to define the mechanism of peripheral MPP+ toxicity in the rat and mouse. Systemically administered MPP+ produced its major pathology in the lung and was typified by perivascular edema. An increase in plasma glutathione disulfide concentrations also resulted, suggesting that MPP+ in analogy to paraquat produces oxidative stress. In addition, the lethality of MPP+ in the mouse was increased by dietary selenium deficiency. These results define in both pathological and chemical terms the potent systemic toxicity of MPP+ and suggest that MPP+, because of its high concentration in primate brain, has the potential to play an important role in the CNS toxicity of MPTP.
Insights
1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes parkinsonism. Its metabolite, 1-methyl-4-phenylpyridine (MPP+), shows potent systemic toxicity, primarily affecting the lungs and causing oxidative stress.
Area of Science:
- Neuroscience
- Toxicology
Background:
- 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is known to induce parkinsonism in primates.
- Metabolism of MPTP to 1-methyl-4-phenylpyridine (MPP+) is considered crucial for its neurotoxic effects.
- Directly assessing MPP+ effects in the brain is challenging, necessitating studies on peripheral toxicity.
Purpose of the Study:
- To elucidate the mechanism of peripheral 1-methyl-4-phenylpyridine (MPP+) toxicity in rats and mice.
- To understand the systemic pathological and chemical effects of MPP+.
Main Methods:
- Systemic administration of 1-methyl-4-phenylpyridine (MPP+) to rats and mice.
- Pathological examination of affected organs, focusing on lung tissue.
- Measurement of plasma glutathione disulfide concentrations.
- Assessment of MPP+ lethality in mice with dietary selenium deficiency.
Main Results:
- Systemic MPP+ administration primarily caused lung pathology, characterized by perivascular edema.
- Increased plasma glutathione disulfide concentrations indicated oxidative stress induced by MPP+.
- Dietary selenium deficiency exacerbated the lethality of MPP+ in mice.
Conclusions:
- 1-methyl-4-phenylpyridine (MPP+) exhibits potent systemic toxicity, with the lungs being a major target organ.
- MPP+ induces oxidative stress, similar to paraquat.
- The findings suggest MPP+ has the potential to significantly contribute to the central nervous system toxicity of MPTP, especially given its high concentration in primate brains.