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The Biochemical Journal Dec 1978The effects of thiol-specific reagents on the amplitude of the electro-olfactogram (E.O.G.) responses elicited from frog olfactory mucosa by pulses of odorant vapours...
The effects of thiol-specific reagents on the amplitude of the electro-olfactogram (E.O.G.) responses elicited from frog olfactory mucosa by pulses of odorant vapours was studied. The impermeant thiol-specific reagent mersalyl [(3-{[2-(carboxymethoxy)-benzoyl]amino}-2-methoxypropyl)hydroxymercury monosodium salt] brings about a rapid decrease in the E.O.G. signal obtained with the odorant pentyl acetate. The extent of the decrease is proportional to the concentration of the mersalyl applied and the effect of the reagent is partially but incompletely reversed by treatment of the labelled mucosa with dithiothreitol. The sites labelled by mersalyl can be protected by pretreating the mucosa with a dilute solution of the odorant pentyl acetate and leaving the solution in contact with the tissue after the addition of mersalyl. When the protecting odorant is washed out of the tissue, the original E.O.G. amplitude is regained. Pentyl acetate applied to the mucosa protected the E.O.G. response to vapour pulses of the following odorants from the effects of mersalyl: n-butyric acid, n-butyl acetate, phenylacetaldehyde and cineole (1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane). The pentyl acetate applied to the mucosa failed to protect the E.O.G. response to vapour pulses of the following odorants from the effects of mersalyl: butan-1-ol, benzyl acetate, nitrobenzene, beta-ionone and linalyl acetate. The significance of the differential protection effects for the odour-quality-coding mechanism in the olfactory primary neurons is discussed. It is suggested that the olfactory code at this level of the olfactory system may be elucidated by chemical-modification methods.
Topics: Acetates; Animals; Anura; Binding Sites; Electrophysiology; Mersalyl; Olfactory Mucosa; Organomercury Compounds; Pentanols; Rana temporaria
PubMed: 311638
DOI: 10.1042/bj1760845 -
European Journal of Biochemistry Apr 2001The accumulation of carnitine was measured in cerebral cortex neurons isolated from adult rat brain. This process was found to be lowered by 40% after preincubation with...
The accumulation of carnitine was measured in cerebral cortex neurons isolated from adult rat brain. This process was found to be lowered by 40% after preincubation with ouabain and with SH-group reagents (N-ethylmaleimide and mersalyl). The initial velocity of carnitine transport was found to be inhibited by 4-aminobutyrate (GABA) in a competitive way (Ki = 20.9 +/- 2.4 mM). However, of various inhibitors of GABA transporters, only nipecotic acid and very high concentrations of 1-[2-([(diphenylmethylene)amino]oxy)ethyl]-1,2,5,6-tetrahydro-3-pyridinecarboxylic acid hydrochloride (NO-711) acid decreased carnitine accumulation while betaine, taurine and beta-alanine had no effect. The GABA transporters expressed in Xenopus laevis oocytes did not transport carnitine. Moreover, carnitine was not observed to diminish the accumulation of GABA in cerebral cortex neurons, which further excluded a possible involvement of the GABA transporter GAT1 in the process of carnitine accumulation, despite the expression of this protein in the cells under study. The absence of carnitine transporter OCTN2 in rat cerebral cortex neurons (K. A. Nałecz, D. Dymna, J. E. Mroczkowska, A. Broër, S. Broër, M. J. Nałecz and R. Cecchelli, unpublished results), together with the insensitivity of carnitine accumulation towards betaines, implies that a novel transporting protein is present in these cells.
Topics: Animals; Betaine; Binding, Competitive; Biological Transport, Active; Carnitine; Carrier Proteins; Cells, Cultured; Cerebral Cortex; Female; GABA Plasma Membrane Transport Proteins; Membrane Proteins; Membrane Transport Proteins; Neurons; Nipecotic Acids; Oocytes; Organic Anion Transporters; Organic Cation Transport Proteins; Oximes; Rats; Rats, Wistar; Solute Carrier Family 22 Member 5; Taurine; Xenopus laevis; beta-Alanine; gamma-Aminobutyric Acid
PubMed: 11277932
DOI: 10.1046/j.1432-1327.2001.02087.x -
The Journal of Toxicological Sciences May 1978The effect of mersalyl on the relaxation of catch by various monoamines was studied in the anterior byssal retractor muscle of Mytilus. As has already been reported,...
The effect of mersalyl on the relaxation of catch by various monoamines was studied in the anterior byssal retractor muscle of Mytilus. As has already been reported, mersalyl blocked the relaxing response to indoleamines but not block that to catecholamines. The relaxations in response to catecholamine-related compounds (dopa, octopamine, tyramine, phenylephrine, beta-phenylethylamine and phenylethanolamine) and hexylamine were, however, antagonized more or less effectively with mersalyl. It was suggested that the catecholamine-related compounds and hexylamine can act on relaxing nerve endings to increase neurotransmitter serotonin in the junctional clefts, and mersalyl antagonizes the relaxation in response to these compounds by blocking the serotonin.
Topics: Animals; Biogenic Amines; Bivalvia; Dose-Response Relationship, Drug; Drug Interactions; In Vitro Techniques; Mersalyl; Muscle Contraction; Muscle Relaxation; Muscle, Smooth; Organomercury Compounds; Seasons
PubMed: 755106
DOI: 10.2131/jts.3.117 -
European Journal of Biochemistry May 1984The phosphate transport protein (PTP) has been isolated from beef heart mitochondria in the presence of cardiolipin and reconstituted in asolectin and...
The phosphate transport protein (PTP) has been isolated from beef heart mitochondria in the presence of cardiolipin and reconstituted in asolectin and phosphatidylcholine vesicles. As expected, the activity of the reconstituted PTP is inhibited by N-ethylmaleimide and mersalyl. It is also inhibited by adriamycin and Br-daunomycin. Storage of isolated mitochondria at -80 degrees C prior to the isolation of the PTP decreases the maximal activity of the unidirectional transport of phosphate (Pi) in reconstituted vesicles. The sensitivity of the system to the four inhibitors remains the same. The inhibition of the PTP by adriamycin is reversed by KCl and prevented by MgSO4. Since the interaction between adriamycin and cardiolipin is of ionic type, KCl apparently replaces adriamycin on the negative charges of cardiolipin. By contrast, MgSO4 complexes adriamycin directly, eliminating its inhibitory effect on the PTP. No PTP activity is found after reconstitution in phosphatidylcholine vesicles in the absence of cardiolipin. Addition of buffer-dispersed cardiolipin to the vesicles restores the Pi-transport activity. The addition of adriamycin to the vesicles together with cardiolipin removes the reactivation. Succinylation of the PTP at pH 8.0 eliminates the inhibitory effect of adriamycin in the reconstituted system. The effects of N-ethylmaleimide and mersalyl are not modified. The succinylated preparation reconstituted in phosphatidylcholine vesicles is reactivated by cardiolipin, but in this case the reactivation is not counteracted by adriamycin. Succinylation of the PTP at pH 9.0 results in its complete inhibition. The results indicate, (a) that the sites of interaction of MalNEt /mersalyl and adriamycin with the PTP X cardiolipin complex are different, and (b) that the adriamycin-binding site in the complex is probably on cardiolipin molecules essential to the PTP activity. It is postulated that succinylation of the PTP prevents the interaction of adriamycin with these molecules.
Topics: Animals; Biological Transport; Cardiolipins; Carrier Proteins; Catalysis; Cattle; Doxorubicin; Ethylmaleimide; Hydrogen-Ion Concentration; Liposomes; Mersalyl; Mitochondria, Heart; Phosphate-Binding Proteins
PubMed: 6723644
DOI: 10.1111/j.1432-1033.1984.tb08123.x -
Biochimica Et Biophysica Acta Jul 2013To find out whether and how the adenine nucleotide translocator-1 (ANT-1) inhibition due to NH2htau and Aβ1-42 is due to an interplay between these two Alzheimer's...
To find out whether and how the adenine nucleotide translocator-1 (ANT-1) inhibition due to NH2htau and Aβ1-42 is due to an interplay between these two Alzheimer's peptides, ROS and ANT-1 thiols, use was made of mersalyl, a reversible alkylating agent of thiol groups that are oriented toward the external hydrophilic phase, to selectively block and protect, in a reversible manner, the -SH groups of ANT-1. The rate of ATP appearance outside mitochondria was measured as the increase in NADPH absorbance which occurs, following external addition of ADP, when ATP is produced by oxidative phosphorylation and exported from mitochondria in the presence of glucose, hexokinase and glucose-6-phosphate dehydrogenase. We found that the mitochondrial superoxide anions, whose production is induced at the level of Complex I by externally added Aβ1-42 and whose release from mitochondria is significantly reduced by the addition of the VDAC inhibitor DIDS, modify the thiol group/s present at the active site of mitochondrial ANT-1, impair ANT-1 in a mersalyl-prevented manner and abrogate the toxic effect of NH2htau on ANT-1 when Aβ1-42 is already present. A molecular mechanism is proposed in which the pathological Aβ-NH2htau interplay on ANT-1 in Alzheimer's neurons involves the thiol redox state of ANT-1 and the Aβ1-42-induced ROS increase. This result represents an important innovation because it suggests the possibility of using various strategies to protect cells at the mitochondrial level, by stabilizing or restoring mitochondrial function or by interfering with the energy metabolism providing a promising tool for treating or preventing AD.
Topics: Adenine Nucleotide Translocator 1; Adenosine Diphosphate; Adenosine Triphosphate; Alzheimer Disease; Amyloid beta-Peptides; Animals; Cells, Cultured; Cerebellum; Cytoplasmic Granules; Energy Metabolism; Enzyme Inhibitors; Mersalyl; Mitochondria; Models, Neurological; Oxygen Consumption; Peptide Fragments; Polarography; Rats; Rats, Wistar; Reactive Oxygen Species; Superoxides; tau Proteins
PubMed: 23583906
DOI: 10.1016/j.bbabio.2013.04.001 -
European Journal of Biochemistry Jul 1992The ornithine/citrulline carrier from rat liver mitochondria, solubilized with Triton X-100 and partially purified on hydroxyapatite, was identified and completely...
The ornithine/citrulline carrier from rat liver mitochondria, solubilized with Triton X-100 and partially purified on hydroxyapatite, was identified and completely purified by PD-10, DEAE-Sephacel and celite chromatography. On SDS/polyacrylamide gel electrophoresis, the purified ornithine/citrulline carrier consisted of a single protein band with an apparent molecular mass of 33.5 kDa. When reconstituted into liposomes the ornithine carrier protein catalyzed an active mersalyl sensitive ornithine/ornithine exchange. It was purified 438-fold with a recovery of 38% and a protein yield of 0.09% with respect to the extract derived from mitoplasts. The purified and reconstituted protein did not catalyze a significant unidirectional transport of ornithine. Citrulline was found to be the best countersubstrate for the transport of ornithine, followed by lysine and arginine. The exchange activity was inhibited by several sulphydryl reagents.
Topics: Animals; Biological Transport; Cardiolipins; Citrulline; Detergents; Intracellular Membranes; Liposomes; Membrane Proteins; Mitochondria, Liver; Molecular Weight; Ornithine; Rats
PubMed: 1633803
DOI: 10.1111/j.1432-1033.1992.tb17070.x -
The Biochemical Journal Mar 1975The kinetics of sulphate uptake catalysed by the dicarboxylate carrier were measured. The Km value for sulphate is about 0.3 mM. A completely competitive relation exists...
The kinetics of sulphate uptake catalysed by the dicarboxylate carrier were measured. The Km value for sulphate is about 0.3 mM. A completely competitive relation exists between the influxes of sulphate and malonate, whereas the relation between sulphate and phosphate is of the mixed type. The inhibition of sulphate influx by mersalyl and bathophenanthroline is similar to that of malonate influx and different from the inhibition of phosphate influx. It is considered that sulphate and malonate probably bind to the same locus on the carrier, whereas phosphate occupies a different site. The possible implications of this conclusion are discussed.
Topics: Animals; Binding Sites; Binding, Competitive; Biological Transport, Active; In Vitro Techniques; Kinetics; Malonates; Mitochondria, Liver; Phenanthrolines; Phosphates; Rats; Sulfates
PubMed: 1147910
DOI: 10.1042/bj1460667 -
Biochimica Et Biophysica Acta Mar 1988The importance of sulfhydryl (SH) groups in maintenance of physicochemical properties of the rat hepatic Ah receptor was demonstrated using a variety of sulfhydryl...
The importance of sulfhydryl (SH) groups in maintenance of physicochemical properties of the rat hepatic Ah receptor was demonstrated using a variety of sulfhydryl (SH)-modifying reagents. Inhibition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) specific binding was approximately equivalent by 5,5'-dithiobis(2-nitrobenzoate), mersalyl, N-ethylmaleimide, and p-chloromercuriphenylsulfonate, whose inhibition curves were steep in the concentration range close to that of nonprotein SH groups in cytosol (ED50 values 50-200 microM or 13-48 nmol/mg cytosolic protein). Inhibition by p-hydroxymercuribenzoate (PHMB), although exhibiting a lower ED50, was more gradual over this range; iodoacetamide was an order of magnitude less potent. The ability of dithiothreitol to reverse binding inhibition induced by 150 microM (approximately 60 nmol/mg protein) mersalyl diminished with time; it decreased more rapidly in the simultaneous presence of TCDD and mersalyl than when mersalyl was present alone, consistent with increased accessibility of key SH group(s) due to conformational changes attending TCDD-receptor complex formation. Brief exposure of unoccupied receptor to mersalyl prior to TCDD binding caused slower sedimentation of the complex in 0-KCl sucrose gradients and alterations in its elution profiles on DEAE- and DNA-Sepharose suggestive of some impairment of the transformation process. When reagents were added to the transformed TCDD-receptor complex, loss of binding was observed only at concentrations which were an order of magnitude higher than those inhibiting TCDD binding. Loss of binding by each reagent was biphasic, and except for that caused by mersalyl, was not complete even after 6-8 h. Dithiothreitol was able to reverse the effects of mersalyl or PHMB only partially and only if added during the early phase (10-30 min) of binding loss. Mersalyl was much more potent in disrupting the untransformed than the transformed TCDD receptor complex. Physical alteration of the mersalyl-treated TCDD-receptor complex was evident from gel filtration, sucrose gradients, and DNA- and DEAE-Sepharose chromatography. Our results are in striking contrast to the effects of these reagents on steroid receptors, whose bound steroid hormone ligand is rapidly and reversibly displaced by lower concentrations of reagent.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Animals; Cytosol; DNA; DNA-Binding Proteins; Dithiothreitol; Kinetics; Liver; Male; Mersalyl; Oxidation-Reduction; Polychlorinated Dibenzodioxins; Protein Binding; Rats; Receptors, Aryl Hydrocarbon; Receptors, Drug; Structure-Activity Relationship; Sulfhydryl Reagents; Surface Properties
PubMed: 2831991
DOI: 10.1016/0304-4165(88)90037-2 -
The Journal of Biological Chemistry Nov 1977
Topics: Animals; Cattle; Energy Metabolism; Hydrogen-Ion Concentration; Mersalyl; Mitochondria; Mitochondria, Heart; Mitochondrial Swelling; Nigericin; Nitrates; Oxygen Consumption; Potassium; Sodium; Succinates
PubMed: 21185
DOI: No ID Found -
Biochemical Pharmacology Jun 1986It was shown recently that the antiaggregating agent ticlopidine and some of its analogues inhibit the energy-conserving mechanism in mitochondria [Abou-Khalil et al.,...
It was shown recently that the antiaggregating agent ticlopidine and some of its analogues inhibit the energy-conserving mechanism in mitochondria [Abou-Khalil et al., Biochem. Pharmac. 33, 3893 (1984)]. In the present investigation, the mechanism of inhibition by these drugs was investigated by studying their effects on key reactions of oxidative phosphorylation. Liver mitochondria were isolated from Sprague-Dawley male rats, and the interactions of ticlopidine and six of its analogues with those key reactions were tested. We found: The transport of phosphate, glutamate and succinate into mitochondria was not affected significantly by ticlopidine or any of its analogues; however, it was inhibited by both mersalyl and N-ethylmaleimide as expected. There was no inhibitory effect of the tested drugs on the mitochondrial [3H]ADP translocation activity; rather, ticlopidine produced a concentration-dependent increase of that activity, reaching 54% with 20 micrograms/ml. Ticlopidine and its analogue, PCR 5325, increased the latent ATPase activity by about 400% and the DNP-dependent ATPase by about 50%. Also, PCR 4099 caused a 115% increase in the latent activity, whereas the effects of the remaining analogues varied from slight activation to slight inhibition. Under nonphosphorylation conditions, the mitochondrial H+ extrusion resulting from succinate oxidation was inhibited by ticlopidine in a concentration-dependent manner reaching a quasi total inhibition with 40 micrograms/ml. While PCR 5325 gave results similar to ticlopidine, PCR 4099 was less inhibitory and the other analogues were ineffective. These data indicate that the inhibitory action caused by ticlopidine and some of its analogues on oxidative phosphorylation does not reside at one particular site in the mitochondrial membrane; rather, the inhibition seems to be the outcome of profound alterations in mitochondrial ADP translocase, latent ATPase, and proton translocation in the respiratory chain.
Topics: Adenosine Diphosphate; Adenosine Triphosphatases; Animals; Anticoagulants; Biological Transport; Energy Metabolism; Kinetics; Male; Mitochondria, Liver; Mitochondrial ADP, ATP Translocases; Oxygen Consumption; Platelet Aggregation; Rats; Rats, Inbred Strains; Structure-Activity Relationship; Thiophenes; Ticlopidine
PubMed: 2941020
DOI: 10.1016/0006-2952(86)90303-5