Inhibitory effects of indicaxanthin on mouse ileal contractility: Analysis of the mechanism of action

2011 ◽  
Vol 658 (2-3) ◽  
pp. 200-205 ◽  
Author(s):  
Sara Baldassano ◽  
Alessandra Rotondo ◽  
Rosa Serio ◽  
Maria Antonietta Livrea ◽  
Luisa Tesoriere ◽  
...  
2004 ◽  
Vol 147 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kei Ohkimoto ◽  
Ming-Yih Liu ◽  
Masahito Suiko ◽  
Yoichi Sakakibara ◽  
Ming-Cheh Liu

Molecules ◽  
2013 ◽  
Vol 18 (9) ◽  
pp. 11022-11032 ◽  
Author(s):  
Cristiane de Oliveira ◽  
Lucimara Comunello ◽  
Érica Maciel ◽  
Scheron Giubel ◽  
Alessandra Bruno ◽  
...  

1993 ◽  
Vol 264 (5) ◽  
pp. C1270-C1277 ◽  
Author(s):  
H. C. Palfrey ◽  
S. Leung

The inhibitory effect of ethacrynic acid (EA) and a variety of its derivatives on Na-K-2Cl cotransport in avian erythrocytes was investigated. The most potent compound tested was the adduct of EA with L-cysteine, with an IC50 of 7.2 x 10(-7) M. EA itself, dihydro-EA, EA-D-cysteine, and adducts of EA with other sulfhydryl (-SH) compounds were much less potent. The mechanism of action of EA and EA-L-cysteine differed in several respects: 1) EA-L-cysteine acted more rapidly than EA (half times of < 1 and 4 min, respectively, at 37 degrees C); 2) the action of EA-L-cysteine was reversible by washing, whereas that of EA was not; and 3) the degree of inhibition by EA-L-cysteine varied with medium [K], whereas that of EA did not. The inhibitory effects of both EA-L-cysteine and EA were affected by medium [Na] and [Cl]. We conclude that EA-L-cysteine does not "deliver" EA to transport-related -SH residues or act as an alkylating agent but has some stereospecific effect on cotransport that is a property of the entire molecule. EA does appear to inhibit cotransport by alkylating -SH residues, as closely related compounds lacking the ability to covalently react with such groups were reversible, and other -SH reagents (e.g., N-ethylmaleimide) also inhibited cotransport. EA, EA-L-cysteine, and EA-D-cysteine all inhibited [3H]bumetanide binding to membranes from activated avian erythrocytes at concentrations similar to those that inhibited cotransport. It is possible that the EA and bumetanide types of diuretics interact with closely apposed sites on the Na-K-2Cl cotransporter.


1981 ◽  
Author(s):  
B Martin ◽  
C Bonne

We have recently reported that PGE2 counteracted the anti-aggregating action of PGE1 and of other PG by inhibiting the adenylate cyclase system. But this effect is not due to the interference with anti-aggregating PG receptors. In this study, the mechanism of action of the c AMPlowering effect of PGE2 has been further investigated.Suspensions of aspirin-washed human platelets were incubated for 1 min at 37°C in the presence of papaverine (0.5mM) with PGE1 , PGE2, U46619, a chemical analog of PGH2, 13-azaprostanoic acid, a specific antagonist of TxA2, either alone or in various associations. The c AMP concentration was determined by protein binding assays in platelet extracts. PGE2 (l50nM) and U46619 (1μM) inhibited the rise in c AMP induced by PGE1 (30nM) On the other hand, when 13-azaprostanoic acid (507#x03BC;M) was added to the incubate, the inhibitory effects of these compounds were suppressed.These results support the conclusion that TxA2 and U46619 act on a unique receptor which triggers the c AMP-lowering effect and suggest that PGE2 antagonizes the anti-aggregating PG through interaction with this receptor.


2019 ◽  
Vol 48 (8) ◽  
pp. 1619-1625
Author(s):  
Jasmine Siew Min Chia ◽  
Ammar Izzati Amir Ramadan ◽  
Farihah Hanani Ghazali ◽  
Siong Jiun Wong ◽  
Mohd Roslan Sulaiman ◽  
...  

2021 ◽  
Author(s):  
Bhargab Deka ◽  
Biswajit Dash ◽  
Alakesh Bharali ◽  
Ashique Ahmed

Ketamine has been extensively used in the medical field for more than 50 years, but its exact mechanism of action remains unknown. It\'s used to induce dissociative anesthesia (a state of profound analgesia, amnesia with light sleep, immobility, and a sense of disassociation from one\'s own body and surroundings). Clinical studies on ketamine as a dissociative anesthetic, a model for psychosis, and as a rapidly acting antidepressant have sparked great interest in understanding its effects at the molecular and cellular level. It exerts uncompetitive inhibitory effects on NMDARs (N-Methyl-D-asperate) and may preferentially affect the function of NMDARs in interneurons. The hypnotic effects of this drug are attributed to its blocking action on NMDA and HCN1 receptors; however, both positive and negative modulation of choline, amine, and opioid systems appears to occur. It is likely that ketamine\'s effect on chronic pain and depression far outlasts its actual levels. This could be due to the hyperglutamatergic state induced by ketamine causing a secondary increase in structural synaptic connectivity. The authors of this review have attempted to highlight the action of ketamine not only on NMDA receptors but also on a variety of biochemical processes and functions found in intercellular environments, which may explain its diverse role in many diseases.


1983 ◽  
Vol 61 (11) ◽  
pp. 1305-1311 ◽  
Author(s):  
Joāo Batista Calixto ◽  
José Gilberto Aucélio ◽  
Danilo Freire Duarte

The inhibitory effect of ketamine on the agonist-induced contraction of isolated rat uteri was compared with that of papaverine and verapamil. Under similar experimental conditions papaverine and verapamil were found to be more potent than ketamine. When preparations were preincubated for 20 min with either ketamine (3 × 10−5 to 10−3 M) or papaverine (10−6 to 10−5 M), a noncompetitive antagonism was observed against oxytocin with [Formula: see text] values of 3.67 ± 0.07 and 5.13 ± 0.10, respectively. A noncompetitive form of antagonism was also observed by papaverine against BaCl2 with [Formula: see text] values of 4.59 ± 0.15, while ketamine produced competitive antagonism with a pA2 value of 4.68 ± 0.12. It was also demonstrated that all three inhibitory drugs interfere competitively with Ca2+ on the rat uteri. However, ketamine was shown to be less potent than verapamil and papaverine in antagonizing the effects owing to an increased Ca2+ concentration in the medium. These results are consistent with previous publications that ketamine has a papaverinelike effect on the rat uteri and suggest that the relaxation promoted in this preparation is due, at least in part, to blockade of the Ca2+ translocation processes.


1974 ◽  
Vol 20 (12) ◽  
pp. 1689-1693 ◽  
Author(s):  
Michael Orlowski ◽  
Manuel Goldman

The hypothesis that chlorpromazine inhibition of bacterial endospore germination acts at the level of hexose monophosphate shunt (HMP) dehydrogenases was tested and substantiated for Bacillus cereus T and Bacillus megaterium. However, this cannot be an exclusive mechanism of action in bacterial systems because inhibitory effects on growth and respiration are caused by the drug even when these HMP enzymes are not present in the organisms.


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