Search results for "ACETYLCHOLINESTERASE"
showing 10 items of 86 documents
Von der symptomatischen zur kausalen Therapie?
2009
Until today the pharmacological therapy of Alzheimer’s disease (AD) is still limited to symptomatic temporary improvement or stabilization of cognitive performance and activities of daily living, and the reduction of neuropsychiatric symptoms of the disease. Available symptomatic treatment options are the acetylcholinesterase inhibitors (ACh-I) donepezil, galantamine, rivastigmine, and the partial N-Methyl-D-Aspartat-(NMDA)-antagonist memantine. Further substances with symptomatic targets, especially selective acetylcholine and histamine receptors, are currently under development. Numerous of disease-modifying substances mainly targeting components of the amyloidogenic pathway of AD are pre…
Galantamine is an allosterically potentiating ligand of the human α4/β2 nAChR
2000
Galantamine (ReminyI ) is a novel drug treatment for mild to moderate Alzheimer's disease (AD). Originally established as a reversible inhibitor of the acetylcholine-degrading enzyme acetylcholinesterase (AChE), galantamine also acts as an allosterically potentiating ligand (APL) on nicotinic acetylcholine receptors (nAChR). Having previously established this second mode of action on nAChRs from murine brain, we demonstrate here the same action of galantamine on the most abundant nAChR in the human brain, the α4/β2 subtype. This nAChR-sensitizing action is not a common property of all, or most, AChE inhibitors, as is shown by the absence of this effect for other therapeutically applied AChE…
Seasonal screening of AChE, GSH and gonad histology, in European sea bassDicentrarchus labraxL. reared in three different fish farms
2013
The aim of this work was to do a preliminary seasonal screening of ecotoxicological biomarkers in European sea bass Dicentrarchus labrax in three different fish farms, to know if the different location and typology can discriminate them. A set of selected biomarkers of xenobiotic exposure, such as acetylcholinesterase (AChE) activity, Glutathione (GSH) and gonad morphology were investigated seasonally in male European sea bass D. labrax (L.) reared in three different intensive farms: a land-based farm of cement tanks (T), an in-shore sea cages farm (C1) and an off-shore sea cages farm (C2). The results showed that both location and typology can discriminate AChE activity, GSH content and go…
A biochemical study of the effects of tributyltin on unfertilized eggs, embryos and larvae of the sea squirt Ciona intestinalis
2009
We have used unfertilized eggs, embryos and larvae of the sea squirt Ciona intestinalis (Ascidiacea, Urochordata) to study the effects of tributyltin (TBT) on acetylcholine esterase (AChE) activity. Our results showed an increase of AChE enzyme activity levels after TBT exposure in both unfertilized eggs and embryos. The effects of TBT were more pronounced during the gastrula stage, while no differences between exposed larvae and controls were observed. A mechanism of TBT action on enzyme activity during ascidian embryonic development and the possibility of employing AChE in C. intestinalis as a biomarker of TBT exposure are suggested and discussed.
Effect of sublethal concentrations of copper sulphate on seabreamSparus auratafingerlings
2007
The gilthead seabream is the most important Mediterranean aquacultured fish species. The main objective of this study was to investigate whether copper sulphate bath treatments used routinely in aquaculture have effects on important physiological functions of early life stages of the gilthead seabream (Sparus aurata). Fingerlings (80-90 days, 0.27 ± 0.06 g) were exposed to copper sulphate baths at 0, 0.25, 0.5 and 1.5 mg L −1 during 24 h. Effects on the central nervous function were evaluated analysing brain acetylcholinesterase activity (AChE). Oxidative stress was assessed by the quantification of lipid peroxidation (LP). Heat shock proteins (HSP70) were used as a general response to chem…
Expression and possible functions of the cholinergic system in a murine embryonic stem cell line.
2007
The expression of a cholinergic system during embryonic development is a widespread phenomenon. However, no precise function could be assigned to it during early pre-neural stages and there are only few studies that document when it precisely starts to be expressed. Here, we examined the expression of cholinergic components in a murine embryonic stem cell line by RT-PCR, histochemistry, and enzyme activity measurements; the acetylcholine (ACh) content was measured by HPLC. We have demonstrated that embryonic stem cells express ACh, acetylcholine receptors, choline acetyltransferase (ChAT), acetyl- and butyryl-cholinesterase (AChE and BChE). Butyryl-cholinesterase (BChE) expression was highe…
Acetylcholinesterase activity in juvenileCiona intestinalis(Ascidiacea, Urochordata) after exposure to tributyltin
2012
The acetylcholinesterase (AChE) activity has been studied in 4-day post-fertilization juveniles of Ciona intestinalis exposed to tributyltin (TBT) at 10-5 M using the histochemical method of Karnovsky and Roots. Relative to vertebrate tissues and organs, the development of adult form of ascidians is interesting, because the analysis of many nuclear genes indicated that the ascidians are the closest living relatives of the vertebrates. Therefore, toxicity research using different approaches could provide data for comparative studies with vertebrates. AChE is over-expressed under chemical stress and in some diseases of vertebrates. Therefore, AChE is considered a biomarker of environmental co…
Uptake of Acetylcholine by Bean Hypocotyl Hooks
1978
Summary The uptake of acetylcholine by etiolated hypocotyl hooks of beans ( Phaseolus vulgaris L.) is influenced by light and the pH-value of the incubation medium. Acetylcholine is hydrolysed up to 90 % during the uptake. The hydrolysis is inhibited by pH-value lower than 6.0 and by eserine, an inhibitor of the acetylcholinesterase. The high amount of hydrolysis is a serious problem in experiments involving acetylcholine and necessitates the inclusions of adequate controls without which direct effects of acetylcholine cannot be distinguished from reactions of its metabolic products.
Chapter 17: The cholinesterases: a discussion of some unanswered questions
1993
Publisher Summary During the past three decades, a vast body of specificity and kinetic data relating to the cholinesterases has accumulated, which must now be explained by the extremely interesting new sequence and X-ray crystallographic results presented by MassouliC et al. As this chapter shows, the cholinesterases are remarkable among enzymes in having a broad specificity embracing both charged and uncharged substrates but with a clearly expressed preference, at any rate in the aliphatic series, for the acylcholine configuration: a classical example of the principle of complementariness between substrate and active site as the basis for enzyme action. It is well known that AChE exists i…
Chemie an starren Grenzflächen, 10. Kinetisches Verhalten einiger an „Isothiocyanato-Aerosil” immobilisierter Esterasen – Analogversuche mit Insulin
1988
Amino-Aerosil wird mit Thiophosgen nach Gl. (1) in Isothiocyanato-Aerosil 2 (NCS-Aerosil) ubergefuhrt. Trypsin, Cholinesterase und Acetylcholinesterase werden an 2 nach Gl. (2) immobilisiert. Die Aktivitat der immobilisierten Esterasen wird untersucht auf (a) Lagerstabilitat, (b) Temperaturbestandigkeit und (c) pH-Abhangigkeit. Das kinetische Verhalten der immobilisierten Enzyme wird verglichen mit dem der freien, aber mit n-Butylisothiocyanat behandelten Esterasen. Am Beispiel der Cholinesterase, die uber unterschiedliche Ankergruppen mit Aerosil verknupft wurde, wird der Einflus unterschiedlicher Spacergruppen auf die Hydrolysegeschwindigkeit studiert. Aerosile, die mit Acetylcholin-Analo…