Search results for "Cholines"
showing 10 items of 241 documents
Presynaptic nicotine receptors mediating a positive feed-back on transmitter release from the rat phrenic nerve.
1986
The effects of 1,1-dimethyl-4-phenylpiperazinium (DMPP) and of nicotine receptor antagonists on [3H]acetylcholine release from the rat phrenic nerve preincubated with [3H]choline were investigated in the absence and presence of cholinesterase inhibitors (presynaptic effects). Additionally, the effects of hexamethonium and tubocurarine on the muscle contraction of the indirectly stimulated diaphragm were examined (postsynaptic effects). DMPP (1-30 microM) increased (76-92%), whereas hexamethonium (0.001-1 mM) and tubocurarine (1-10 microM) decreased (52-60%) the release of [3H]acetylcholine following a train of 100 pulses at 5 Hz. The release caused by a longer train (750 pulses at 5 Hz) was…
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…
The release of choline from phospholipids mediated by beta-adrenoceptor activation in isolated hearts.
1986
The resting efflux of choline into the perfusate (Tyrode's solution) of isolated hearts was equal to the rate, at which choline was liberated from phospholipid degradation (Lindmar et al. 1986). Infusion of isoprenaline (2 X 10(-7) mol/l), forskolin (1-3 X 10(-6) mol/l) or 3-isobutyl-1-methylxanthine (IBMX; 3 X 10(-4) mol/l) for 40 min markedly enhanced the efflux of choline. The increase was linear during the experimental period and, in the case of isoprenaline, was blocked by 3 X 10(-7) mol/l atenolol. In the guinea-pig heart, IBMX at a threshold concentration of 10(-4) mol/l shifted the concentration-response curve for the effect of forskolin on the efflux of choline to the left by one l…
Galantamine is an allosterically potentiating ligand of neuronal nicotinic but not of muscarinic acetylcholine receptors.
2003
Galantamine (Reminyl), an approved treatment for Alzheimer's disease (AD), is a potent allosteric potentiating ligand (APL) of human alpha 3 beta 4, alpha 4 beta 2, and alpha 6 beta 4 nicotinic receptors (nAChRs), and of the chicken/mouse chimeric alpha 7/5-hydroxytryptamine3 receptor, as was shown by whole-cell patch-clamp studies of human embryonic kidney-293 cells stably expressing a single nAChR subtype. Galantamine potentiates agonist responses of the four nAChR subtypes studied in the same window of concentrations (i.e., 0.1-1 microM), which correlates with the cerebrospinal fluid concentration of the drug at the recommended daily dosage of 16 to 24 mg. At concentrations10 microM, gal…
Phosphatidylcholine covalently linked to a methacrylate-based monolith as a biomimetic stationary phase for capillary liquid chromatography
2015
Abstract In this study a strategy to immobilize phospholipids onto a polymer-based stationary phase is described. Methacrylate-based monoliths in capillary format (150 × 0.1 mm) were modified by soybean phosphatidylcholine through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide coupling to obtain stationary phases suitable to mimic cell surface membranes. The covalent coupling reaction involves the phosphate group in phospholipids; therefore, the described methodology is suitable for all types of phospholipids. Immobilization of soy bean phosphatidylcholine on the monolith was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy and gas chromatography-mass spectro…
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…
Characterization of choline efflux from the perfused heart at rest and after muscarine receptor activation.
1986
The resting efflux of choline from perfused chicken hearts varied from 0.4 to 2.6 nmol/g min, but was constant for at least 80 min in the individual experiments. The rate of choline efflux was found to be equal to the rate of choline formation in the heart, which, from the following reasons, was essentially due to hydrolysis of choline phospholipids. Cardiac content of choline phospholipids (7,200 nmol/g) was much higher than that of acetylcholine (5.5 nmol/g). Resting release of acetylcholine was 0.016 nmol/g min and, after inhibition of cholinesterase, only about 0.1 nmol/g min. Resting efflux of choline was reduced by mepacrine, a phospholipase A2 inhibitor, by perfusion with a Ca2+-free…
Quantitative structure-activity relationships for the toxicity of organophosphorus and carbamate pesticides to the Rainbow trout Onchorhyncus mykiss.
2006
This study has investigated the development of quantitative structure-activity relationships (QSARs) for the toxicity to rainbow trout Onchorhyncus mykiss Walbaum of 75 organophosphorus and carbamate pesticides. The toxicity data were obtained from an openly available toxicological database and were selected to be representative of a single endpoint. A large number of physicochemical and structural descriptors were calculated for the pesticides. QSAR models were developed using multiple linear regression and partial least-squares analyses. Following the removal of a small number of outliers, predictive QSARs were developed on small numbers of mechanistically relevant descriptors. Applying m…
(±)- BIGI-3h: Pentatarget-Directed Ligand combining Cholinesterase, Monoamine Oxidase, and Glycogen Synthase Kinase 3β Inhibition with Calcium Channe…
2021
Multitarget-directed ligands (MTDLs) are considered a promising therapeutic strategy to address the multifactorial nature of Alzheimer's disease (AD). Novel MTDLs have been designed as inhibitors of human acetylcholinesterases/butyrylcholinesterases, monoamine oxidase A/B, and glycogen synthase kinase 3β and as calcium channel antagonists via the Biginelli multicomponent reaction. Among these MTDLs, (±)-BIGI-3h was identified as a promising new hit compound showing in vitro balanced activities toward the aforementioned recognized AD targets. Additional in vitro studies demonstrated antioxidant effects and brain penetration, along with the ability to inhibit the aggregation of both τ protein…
Acute effects of low doses of methyl parathion on human EEG.
2005
Abstract Biological monitoring of workers exposed to organophosphates consists mainly of measuring serum or erythrocyte cholinesterase activity. However, animal experiments and a field study suggest that quantitative analysis of EEG may be more sensitive. In a parallel group design, 25 farmers were investigated, spraying methyl parathion or water for 50 min. EEG was recorded before and after spraying. Serum and erythrocyte cholinesterase activity was compared with intraindividual pre-exposure values. Plasma methyl parathion concentrations ranged up to 12.1 μg/l, methyl paraoxon was not detectable. Based on plasma concentrations, two exposed subgroups were defined. In EEG recorded with close…