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Neuroprotective effect of riluzole in MPTP-treated mice
1Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Science and Medicine, Aoba-yama, Sendai 980-8578, Japan. tsuaraki@mail.cc.tohoku.ac.jp
Abstract:
The neuroprotective effects of riluzole, a Na(+) channel blocker with antiglutamatergic activity, and MK-801, a blocker of N-methyl-D-aspartate (NMDA) receptors, were compared in the model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced depletion of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels in mice. The mice were injected intraperitoneally (i.p.) with four administrations of MPTP (10 mg/kg) at 1 h intervals and then the brains were analyzed 1, 3 and 7 days after the treatment. Dopamine and DOPAC levels were significantly decreased in the striatum from 1 day after MPTP treatment. A severe depletion in dopamine and DOPAC levels was found in the striatum 3 and 7 days after MPTP treatment. Riluzole antagonized the MPTP-induced decrease in dopamine, DOPAC and HVA levels in the striatum. On the other hand, MK-801 prevented the MPTP-induced decrease in DOPAC levels, but not in dopamine levels in the striatum. An immunohistochemical study indicated that riluzole can protect against MPTP-induced neuronal damage in the substantia nigra. These results suggest that riluzole is effective against MPTP-induced neurodegeneration of the nigrostriatal dopaminergic neuronal pathway.
Insights
Riluzole, a neuroprotective drug, effectively counteracted 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopamine depletion and neuronal damage in mice. MK-801 showed limited neuroprotection against MPTP effects.
Area of Science:
- Neuroscience
- Pharmacology
- Neuroprotection
Background:
- 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that induces Parkinsonism-like symptoms by depleting dopamine.
- Riluzole and MK-801 are drugs with neuroprotective potential, targeting Na(+) channels and NMDA receptors, respectively.
Purpose of the Study:
- To compare the neuroprotective efficacy of riluzole and MK-801 in an MPTP-induced mouse model of dopamine depletion.
- To investigate the impact of these drugs on dopamine, DOPAC, and HVA levels in the striatum and neuronal damage in the substantia nigra.
Main Methods:
- Mice received MPTP injections to induce dopamine depletion.
- Brain tissue was analyzed for dopamine, DOPAC, and HVA levels at 1, 3, and 7 days post-treatment.
- Immunohistochemistry was used to assess neuronal damage in the substantia nigra.
Main Results:
- MPTP significantly decreased dopamine, DOPAC, and HVA levels in the striatum.
- Riluzole effectively antagonized the MPTP-induced depletion of dopamine, DOPAC, and HVA.
- MK-801 partially protected against DOPAC depletion but not dopamine depletion and did not prevent neuronal damage.
Conclusions:
- Riluzole demonstrates significant neuroprotective effects against MPTP-induced nigrostriatal dopaminergic pathway degeneration.
- Riluzole is a promising therapeutic agent for conditions involving dopaminergic neurodegeneration.
- MK-801 exhibits limited neuroprotective capacity in this MPTP model compared to riluzole.