The mechanism by which carbamate pesticides inhibit rat alpha4beta2 nicotinic acetylcholine (ACh) receptors (nAChRs) expressed in Xenopus laevis oocytes has been investigated using the two-electrode voltage clamp technique. Carbaryl, S-ethyl N,N-dipropylthiocarbamate (EPTC), and fenoxycarb inhibit ACh-induced ion currents in a concentration-dependent way. EPTC and fenoxycarb inhibit ion currents induced by 1 mM ACh with 3-fold to 5-fold higher potency than ion currents induced by 1 microM ACh. The potency of carbaryl appears to be independent of ACh concentration. Fenoxycarb displaces (3)H-epibatidine bound to alpha4beta2 (nAChRs) with a K(i) of 750 microM, which is much higher than the functional IC(50) of 2.3-11 microM. This shows that the inhibition of ion current by the carbamate is a noncompetitive effect. Inhibition by fenoxycarb is independent of the state of the ion channel. The rate of onset of inhibition is enhanced, and the rate of reversal of inhibition is reduced, when the concentration of fenoxycarb is increased. The rate of reversal of inhibition is also reduced when the period of exposure to fenoxycarb is increased. The time- and concentration-dependent inhibition of nAChR-mediated ion current by fenoxycarb is accounted for by a two-step mechanism involving a rapid blocked state and a sequential more stably blocked or desensitized state.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1093/toxsci/kfh261 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Multidimensional library for the improved identification of per- and polyfluoroalkyl substances (PFAS).
Sci Data
January 2025
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
As the occurrence of human diseases and conditions increase, questions continue to arise about their linkages to chemical exposure, especially for per-and polyfluoroalkyl substances (PFAS). Currently, many chemicals of concern have limited experimental information available for their use in analytical assessments. Here, we aim to increase this knowledge by providing the scientific community with multidimensional characteristics for 175 PFAS and their resulting 281 ion types.
View Article and Find Full Text PDFLiquid-based encapsulation for implantable bioelectronics across broad pH environments.
Nat Commun
January 2025
Department of Biomedical Engineering and the Institute of Materials Science, University of Connecticut, Storrs, CT, 06269, USA.
Wearable and implantable bioelectronics that can interface for extended periods with highly mobile organs and tissues across a broad pH range would be useful for various applications in basic biomedical research and clinical medicine. The encapsulation of these systems, however, presents a major challenge, as such devices require superior barrier performance against water and ion penetration in challenging pH environments while also maintaining flexibility and stretchability to match the physical properties of the surrounding tissue. Current encapsulation materials are often limited to near-neutral pH conditions, restricting their application range.
View Article and Find Full Text PDFAtomically thin high-entropy oxides via naked metal ion self-assembly for proton exchange membrane electrolysis.
Nat Commun
January 2025
School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
Designing efficient Ruthenium-based catalysts as practical anodes is of critical importance in proton exchange membrane water electrolysis. Here, we develop a self-assembly technique to synthesize 1 nm-thick rutile-structured high-entropy oxides (RuIrFeCoCrO) from naked metal ions assembly and oxidation at air-molten salt interface. The RuIrFeCoCrO requires an overpotential of 185 mV at 10 m A cm and maintains the high activity for over 1000 h in an acidic electrolyte via the adsorption evolution mechanism.
View Article and Find Full Text PDFIdenHerb: A strategy for identifying constitutive herbs of herbal products by screening exclusive ions of each herb from large-scale multi-group LC-MS data.
J Chromatogr A
January 2025
Division of Pharmacognosy, School of Pharmaceutical Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 38 Xueyuan Road, Beijing 100191, China; Medical College, Tibet University, Lhasa 850002, China. Electronic address:
Identification of constitutive herbs in an herbal product is critical for ensuring its quality and efficacy. However, current identification methods often lack universality, entail long durations, and involve complex procedures. Therefore, there is an urgent need to develop innovative methods for identifying constitutive herbs.
View Article and Find Full Text PDFGreen and Sustainable Spectrofluorometric Determination of Nitrofurantoin in Pure Form and Water Samples Using Functionalized Carbon Quantum Dots.
Luminescence
January 2025
Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt.
The environmental impact of chemicals used in aquaculture, particularly nitrofurantoin, has raised global concern. Nitrofurantoin, a broad-spectrum antimicrobial, is commonly used in aquaculture despite safety risks. Determination of nitrofurantoin in water samples of fish ponds is necessary to ensure the safety and quality of seafood.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!