Search results for "Cholines"
showing 10 items of 241 documents
Acetylcholine-responsive cargo release using acetylcholinesterase-capped nanomaterials
2019
[EN] Mesoporous silica nanoparticles capped with acetylcholinesterase, through boronic ester linkages, selectively release an entrapped cargo in the presence of acetylcholine.
Synthetic approaches towards huperzine A and B
2013
Huperzine A and B are potent acetylcholinesterase inhibitors and promising against Alzheimer's disease. Completed and formal total syntheses of these medically relevant alkaloids are presented and discussed.
Comparative chemical composition and bioactivity of leaves essential oils from nine Sicilian accessions of Myrtus communis L.
2019
In this study, the essential oils obtained from the leaves of Myrtus communis L. stored in a collection orchard located at the experimental station ‘Orleans’ of the Department of Agricultural and Forest Sciences of the University of Palermo (Italy) were investigated. The essential oils, analysed by gas chromatography–mass spectrometry, revealed the presence of α-pinene, 1,8-cineole, linalool, limonene and myrtenyl acetate as dominant constituents. The neuroprotective effects of M. communis essential oils were investigated by analysing the antioxidant properties and cholinesterases (acetylcholinesterase, AChE, and butyrylcholinesterase, BChE) inhibitory activity. Essential oils from Scopello…
Spectroscopic and Structural Investigation of the Confinement of D and L Dimethyl Tartrate in Lecithin Reverse Micelles
2009
The confinement of D and L dimethyl tartrate in lecithin reverse micelles dispersed in cyclohexane has been investigated by FT-IR, polarimetry, electronic and vibrational circular dichroism (ECD and VCD), 1H NMR, and small-angle X-ray scattering (SAXS). Measurements have been performed at room temperature as a function of the solubilizate-to-surfactant molar ratio (R) at fixed lecithin concentration. The analysis of experimental data indicates that the dimethyl tartrate molecules are solubilized within reverse micelles in proximity to the surfactant head groups in the same way for the D and L forms. The encapsulation of dimethyl tatrate within lecithin reverse micelles involves changes in i…
Compensatory mechanisms enhance hippocampal acetylcholine release in transgenic mice expressing human acetylcholinesterase
2001
Central cholinergic neurotransmission was studied in learning-impaired transgenic mice expressing human acetylcholinesterase (hAChE-Tg). Total catalytic activity of AChE was approximately twofold higher in synaptosomes from hippocampus, striatum and cortex of hAChE-Tg mice as compared with controls (FVB/N mice). Extracellular acetylcholine (ACh) levels in the hippocampus, monitored by microdialysis in the absence or presence of 10(-8)-10(-3) M neostigmine in the perfusion fluid, were indistinguishable in freely moving control and hAChE-Tg mice. Muscarinic receptor functions were unchanged as indicated by similar effects of scopolamine on ACh release and of carbachol on inositol phosphate fo…
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…
Alterations on AChE Activity of the Fish Anguilla anguilla as Response to Herbicide-Contaminated Water
2000
Abstract The inhibition of both total and specific acetylcholinesterase activities was measured in the whole eyes of the yellow eel Anguilla anguilla after exposure to the carbamate thiobencarb. In vivo assays were conducted under a constant flow-through system of thiobencarb-contaminated water (1/60 LC50 96 h=0.22 ppm for 96 h) followed by a recovery period in clean water (192 h more). The results indicated a measurable level of AChE activity on eyes of control eels, which resulted in a sensitive indicator of the presence of thiobencarb in the water. The pesticide induced significant inhibitory effects on AChE activity ranging from 35% in total AChE activity to 75% in specific AChE activit…
Effects of Norepinephrine and Cardiotrophin-1 on Phospholipase D Activity and Incorporation of Myristic Acid Into Phosphatidylcholine in Rat Heart
2004
The present study is part of a project on phospholipase D (PLD) in cardiac hypertrophy and analyzed effects on PLD activity of two growth stimuli, norepinephrine (NE) and cardiotrophin-1 (CT-1), in incubated rat heart. Phosphatidylcholine (PC) was labeled by 3H-myristic acid. PLD produced 3H-phosphatidylethanol (3H-PEth) from 3H-PC in the presence of ethanol and maintained a basal formation of 3H-PEth. Short-term and long-term exposure to NE for 2 or 13 h, respectively, enhanced the formation of 3H-PEth, which was blocked by prazosin. Long-term pretreatment with NE or CT-1 increased the incorporation of 3H-myristic acid into PC, which was blocked by atenolol. When the 3H-PEth formation was …
Toxicity effects of the organic UV-filter 4-Methylbenzylidene camphor in zebrafish embryos
2019
Abstract Ultraviolet (UV) filters are widely used in personal care products and due to their lipophilicity these chemicals tend to bioaccumulate in the aquatic biota. 4-Methylbenzylidene camphor (4-MBC) is one of the most used UV-filters, and it is commonly detected in freshwater fish tissues. This substance is suspected to be an endocrine disruptor due to its interaction with Hypothalamus-Pituitary-Gonadal (HPG) and HP-Thyroid (HPT)-axis. The main objective of this study was to evaluate the effects of 4-MBC on apical endpoints, biochemical markers and on genes involved in endocrine pathways in Danio rerio. Zebrafish embryos were exposed to 4-MBC (0.083–0.77 mg/l) from 0 to 96 h post-fertil…
Inhibitory and excitatory muscarinic receptors modulating the release of acetylcholine from the postganglionic parasympathetic neuron of the chicken …
1992
The effects of muscarinic receptor antagonists on ACh release were studied in the absence or presence of cholinesterase (ChE) inhibition using the isolated perfused chicken heart. Presynaptic inhibitory muscarinic autoreceptor were characterized by determining the potency of various antagonists to enhance [3H]-ACh release evoked by field stimulation (3 Hz, 1 min). The order of potencies was: (±)-telenzepine > atropine > 4-DAMP > silahexocyclium > pirenzepine > hexahydro-siladifenidol > AF-DX 116. The comparison with known pA2 values for M1-, M2- and M3-receptors revealed that the presynaptic autoreceptor meets the criteria of an M1-receptor. Basal, not electrically evoked overflow of unlabe…