Involvement of calcium in 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP)-induced experimental parkinsonism
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Title |
Involvement of calcium in 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP)-induced experimental parkinsonism |
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Creator |
Samantaray, S
Mohanakumar, K P |
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Subject |
Cell Biology & Physiology
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Description |
Parkinson’s disease, a progressive neurodegenerative disorder, involves the selective degeneration of A9 substantia nigra neurons in the brain. In the present study, we hypothesize that the active form of the parkinsonian toxin, 1-methyl-4-phenyl pyridinium ion (MPP+) acts as a Ca2+ channel blocker. The study explores the Ca2+-involvement in this selective neurodegeneration at three levels: (i) subcellular level aiming to assess the intrasynaptosomal Ca2+ flux using Fura-2AM; (ii) tissue level employing HPLC-electrochemistry to monitor dopamine release from striatal slices; and (iii) organism level involving in vivo studies by pharmacologically intervening with L-type dihydropyridine Ca2+ channel agonist, (±)-Bay K8644 and antagonist, nicardipine. The active metabolite, MPP+ was used for in vitro and ex vivo experiments whereas for in vivo investigations, Balb/c mice were injected with MPTP. In vivo effects of calcium channel agonist, Bay K8644 and antagonist, nicardipine with and without MPTP were monitored for different parameters such as monoamine oxidase-B activity, tyrosine hydroxylation, MPP+ formation in the striatum, levels of reduced (GSH) and oxidized glutathione (GSSG), and striatal DA employing HPLC-electrochemistry. In the present study we observed MPP+ causes an increase in intrasynaptosomal Ca2+, culminating in DA release from the striatum, which is sensitive to Ltype dihydropyridine Ca2+, channel modulation. Our studies with (±)-Bay K8644 and nicardipine affirmed the involvement of L-type Ca2+ channels in MPTP-neurotoxicity. Relevant findings from the study proved our hypothesis: MPP+ being a Ca2+ channel blocker, acting at the L-type Ca2+ channels. Keywords: Parkinson’s disease, methylphenyl tetrahydropyridine, calcium, calcium channel, neurodegeneration. |
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Date |
2003
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Type |
Conference or Workshop Item
PeerReviewed |
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Format |
application/pdf
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Identifier |
http://www.eprints.iicb.res.in/1075/1/3_4_JN_2003.pdf
Samantaray, S and Mohanakumar, K P (2003) Involvement of calcium in 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP)-induced experimental parkinsonism. In: Joint Meeting of the International-Society-for-Neurochemistry/Asian-Pacific-Society-for-Neurochemistry, WANCHAI, PEOPLES R CHINA. |
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Relation |
http://onlinelibrary.wiley.com/doi/10.1046/j.1474-1644.2003.2175_9.x/pdf
http://www.eprints.iicb.res.in/1075/ |
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