scholarly journals The Mechanisms of Inhibition of Frog Endplate Currents With Homologous Derivatives of the 1,1-dimethyl-3-oxybutyl Phosphonic Acid

2012 ◽  
pp. 395-404
Author(s):  
E. PRYAZHNIKOV ◽  
A. OSTROUMOV ◽  
O. DRUGININA ◽  
F. VYSKOČIL ◽  
A. SKORINKIN
Keyword(s):  
Mathematical Modeling ◽  
Phosphonic Acid ◽  
Open Channel ◽  
Allosteric Modulation ◽  
Rhythmic Stimulation ◽  
Channel Opening ◽  
Two Component ◽  
Functional Components ◽  
Derivatives Of ◽  
Receptor Channel

The mode of inhibition of endplate currents by four esters of 1,1-dimethyl-3-oxybutyl phosphonic acid with different lipophilicities and molecule lengths were estimated by mathematical modeling based on previous electrophysiological data supplemented by several experiments with rhythmic stimulation. The aim was to discriminate between their receptor and non-receptor effects. It was shown that all esters have a two-component mechanism of depression: inhibition of the receptor open channel and allosteric modulation of the receptor-channel complex. The ratio of both functional components depends on the length and lipophilicity of the esters. Short and less lipophilic esters mostly act as open channel inhibitors and the rate of inhibition substantially depends on the rate of stimulation, i. e. probability of the receptor-channel opening. As the length of the ester radicals and their lipophilicity increased, these compounds were more active as allosteric receptor inhibitors, probably hindering the function of nAChRs from the lipid annulus.

scholarly journals Distinct Mg2+-dependent Steps Rate Limit Opening and Closing of a Single CFTR Cl− Channel

2002 ◽  
Vol 119 (6) ◽  
pp. 545-559 ◽  
Author(s):  
Athanasios G. Dousmanis ◽  
Angus C. Nairn ◽  
David C. Gadsby
Keyword(s):  
Open Channel ◽  
Tight Binding ◽  
Single Channels ◽  
Channel Opening ◽  
Subsequent Exposure ◽  
Cl Channels ◽  
Excised Patches ◽  
Atp Binding And Hydrolysis ◽  
Opening And Closing ◽  
Rate Limit

The roles played by ATP binding and hydrolysis in the complex mechanisms that open and close cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channels remain controversial. In this work, the contributions made by ATP and Mg2+ ions to the gating of phosphorylated cardiac CFTR channels were evaluated separately by measuring the rates of opening and closing of single channels in excised patches exposed to solutions in which [ATP] and [Mg2+] were varied independently. Channel opening was found to be rate-limited not by the binding of ATP alone, but by a Mg2+-dependent step that followed binding of both ATP and Mg2+. Once a channel had opened, sudden withdrawal of all Mg2+ and ATP could prevent it from closing for tens of seconds. But subsequent exposure of such an open channel to Mg2+ ions alone could close it, and the closing rate increased with [Mg2+] over the micromolar range (half maximal at ∼50 μM [Mg2+]). A simple interpretation is that channel closing is stoichiometrically coupled to hydrolysis of an ATP molecule that remains tightly associated with the open CFTR channel despite continuous washing. If correct, that ATP molecule appears able to reside for over a minute in the catalytic site that controls channel closing, implying that the site must entrap, or have an intrinsically high apparent affinity for, ATP, even without a Mg2+ ion. Such stabilization of the open-channel conformation of CFTR by tight binding, or occlusion, of an ATP molecule echoes the stabilization of the active conformation of a G protein by GTP.

scholarly journals Mathematical Modeling of Pollution Transfer in Open Channel

2019 ◽  
pp. 49-50
Author(s):  
Petro Martyniuk ◽  
Oksana Ostapchuk ◽  
Vitalii Nalyvaiko
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Numerical Solution ◽  
Boundary Problem ◽  
Water Flow ◽  
Numerical Experiments ◽  
Open Channel ◽  
Computational Algorithm ◽  
The Mathematical Model

The problem of pollution transfer by water flow in open channel was considered. The mathematical model of the problem was constructed. The numerical solution of the onedimensional boundary problem was obtained. The computational algorithm for solving the problem was programmed to implement. A series of numerical experiments with their further analysis was conducted.

Functional derivatives of (bromomethyl)phosphonic acid

2004 ◽  
Vol 74 (8) ◽  
pp. 1168-1170
Author(s):  
L. K. Kibardina ◽  
M. A. Pudovik ◽  
R. M. Kamalov ◽  
A. N. Pudovik
Keyword(s):  
Phosphonic Acid ◽  
Functional Derivatives ◽  
Derivatives Of

scholarly journals Copper(II) Complexes of Organophoshonic Acids-A Comparative Study

2011 ◽  
Vol 8 (s1) ◽  
pp. S271-S281
Author(s):  
B. Venkateswara Rao ◽  
D. M. Puri
Keyword(s):  
Phosphonic Acid ◽  
Octahedral Geometry ◽  
Spectral Studies ◽  
Diphosphonic Acid ◽  
Paramagnetic Resonance ◽  
Diethylene Triamine ◽  
Coordination Sites ◽  
Infrared Spectral ◽  
Electron Paramagnetic ◽  
Derivatives Of

Polynuclear copper(II) derivatives of 1-hydroxyethylidenediphosphonic acid (HEDP), 1-aminoethylidenediphosphonic acid (AEDP, H4L),α-aminobenzylidene diphosphonic acid (ABDP, H4L), 1-amino-2-carboxyethane- 1,1-diphosphonic acid (ACEDP, H5L), 1,3 diaminopropane-1,1,3,3-tetra-phosphonic acid (DAPTP, H8L), Ethylenediamine-N,N'-bis (dimethyl-methylenephosphonic) acid (EDBDMPO, H4L),o-phenylene-diamine-N,N'-bis (dimethylmethylenephosphonic) acid (PDBDMPO, H4L), diethylene triamine –N,N,N',N',N"N-penta (methylene phosphonic) acid (DETAPMPO, H10L) and diethylene triamine –N,N"-bis (dimethyl methylene phosphonic) acid (DETBDMPO, H4L) have been prepared in aqueous medium. The general formula of derivatives from elemental analysis was found to be Cu2L.XH2O (in case of AEDP, ABDP, EDBDMPO, PDBDMPO, DETBDMPO), Cu5L2.XH2O (in case of ACEDP) Cu4L.XH2O, Cu2H4L. XH2O (in case of DAPTP) and Cu5L.XH2O (in case of DETAPMPO). The electronic spectra have shown them to be six coordinated with slight distortion from octahedral geometry. Antiferromagnetism was inferred from magnetic moment data. Infrared spectral studies were carried out to determine coordination sites. EPR (Electron Paramagnetic Resonance) spectra that supports the presence of tetragonal distortion and antiferromagnetic behaviour, have also been studied.

The synthesis and BK channel-opening activity of N- acylaminoalkyloxime derivatives of dehydroabietic acid

2016 ◽  
Vol 26 (2) ◽  
pp. 283-287 ◽  
Author(s):  
Yong-Mei Cui ◽  
Xin-Lan Liu ◽  
Wen-Ming Zhang ◽  
Hai-Xia Lin ◽  
Tomohiko Ohwada ◽  
...  
Keyword(s):  
Dehydroabietic Acid ◽  
Bk Channel ◽  
Channel Opening ◽  
Derivatives Of
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