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- Soukup, Ondrej, et al.
(author)
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A Resurrection of 7-MEOTA: A Comparison with Tacrine
- 2013
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In: Current Alzheimer Research. - 1567-2050. ; 10:8, s. 893-906
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Journal article (peer-reviewed)abstract
- Alzheimer´s disease (AD) is a progressive neurodegenerative dementia which currently represents one of the biggest threats for the human kind. The cure is still unknown and various hypotheses (cholinergic, amyloidal, oxidative, vascular etc.) are investigated in order to understand the pathophysiology of the disease and on this basis find an effective treatment. Tacrine, the first approved drug for the AD disease treatment, has been reported to be a multitargeted drug, however it was withdrawn from the market particularly due to its hepatotoxicity. Its derivative 7-methoxytacrine (7- MEOTA) probably due to the different metabolization does not exert this side effect. The aim of our study was to compare these two cholinesterase inhibitors from various, mainly cholinergic, points of view relevant for a potential AD drug. We found that 7-MEOTA does not fall behind its more well-known parent compound – tacrine. Furthermore, we found, that 7-MEOTA exerts better properties in most of the tests related to a possible AD treatment. Only the pharmacokinetics and a higher acetylcholinesterase and butyrylcholinesterase inhibitory potency would slightly give advantages to tacrine over 7-MEOTA, but concerning its lower toxicity, better antioxidant properties, interaction with muscarinic and nicotinic receptors and “safer” metabolization provide strong evidence for reconsider 7-MEOTA and its derivatives as candidate molecules for the treatment of AD.
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| 2. |
- Soukup, Ondrej, et al.
(author)
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Methylacridinium and its cholinergic properties.
- 2009
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In: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1029-8428 .- 1476-3524. ; 16:4, s. 372-7
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Journal article (peer-reviewed)abstract
- 10-Methylacridinium iodide (methylacridinium; MA) is an inhibitor of cholinesterases. Inhibitors of acetylcholinesterase (AChE) are used in the treatment of myasthenia gravis, Alzheimer's disease, and in the prophylaxis of poisoning with organophosphates. Using spectrophotometric Ellman's method at 436 nm and commercial enzymes we found that MA inhibits AChE by binding with relatively high potency to the peripheral anionic site (IC(50) = 1.68 +/- 0.14 muM; human recombinant AChE) and equally to its inhibition of butyrylcholinesterase (BuChE; IC(50) = 3.54 +/- 0.27 muM; BuChE from human serum). MA also inhibits the binding of [(3)H]N-methylscopolamine to the muscarinic M2 receptor subtype, possibly in an allosteric manner (IC(50) = 1.90 muM). Functional effects on both the enzyme and the receptor could be observed in contractile studies on the isolated rat bladder. The ability of MA to cross the blood-brain barrier (log P = -0.32; polar surface area 3.88) provides prerequisites for a potential use of the drug in the treatment of neural disorders.
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| 3. |
- Soukup, Ondrej, et al.
(author)
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The effect of HI-6 on cholinesterases and on the cholinergic system of the rat bladder.
- 2008
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In: Neuro endocrinology letters. - 0172-780X. ; 29:5, s. 759-62
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Journal article (peer-reviewed)abstract
- OBJECTIVES: The current standard treatment of organophosphate poisoning consists of an administration of anticholinergic drugs and cholinesterase reactivators (oximes). Oximes can react - except their reactivating effect on cholinesterases - directly with cholinoreceptors. HI-6 is an oxime that may have an inhibitory effect on the muscarinic receptors, too. METHODS: In our work, we have investigated an influence of HI-6 on the acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and on the muscarinic receptors in vitro. The study was conducted using biosensor technique and on the rat bladder using in vitro test (tissue bath; methacholine as muscarinic agonist). IC50 for BChE from human serum was determined to be 1.01x10-6 M and for human erythrocytes AChE 3.31x10-6 M, respectively. CONCLUSION: We assume that the demonstrated contractile response can be attributed to the inhibition of the AChE at the lower concentration and to a predominant inhibition of muscarinic receptor at higher concentration of compound tested.
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