Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The subsynaptic area of mouse diaphragm fibres was hyperpolarized by 1--2 mV during local curarization of the junctional zone in the presence of the reversible anticholinesteraze prostigmine (6 X 10(-6) M), or after treatment of the muscle with organophosphate cholinesterase inhibitor Soman. In a solution containing 5 mM K+ the mean hyperpolarization was 1.1 +/- 0.27 mV at mean resting potential--70 mV. After adding 2 X 10(-5) M ouabain the hyperpolarization increased to 1.5 +/- 0.25 mV. Removal of potassium ions from the bathing medium also increased curare induced hyperpolarization to 1.80 +/- 0.40 mV. Reactivation of membrane ATP-ase by addition of K+ after a period in K+-free medium reduced the hyperpolarization to zero, where measurements were performed 10--20 min after the readdition. It was concluded that spontaneous non-quantal leakage of acetylcholine occurs at the mouse neuromuscular junction, as it does in the frog (ref. Katz and Miledi 1977). Conditions which block the Na+-K+-dependent ATP-ase of nerve terminals increased the continuous leakage of ACh and activation of the pump decreased it.
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PMID:Electrophysiological examination of transmitter release in non-quantal form in the mouse diaphragm and the activity of membrane ATP-ase. 3 68

Acute experiments were conducted on male rats; it was revealed that electrical stimulation of the nuclei of the anterior hypothalamus led to reduction of choleresis and to a fall of the potassium content in the bile, increase of permeability of the connective tissue stroma of the liver and of cell membranes of hepatocytes. Stimulation of the posterior hypothalamic nuclei induced an increase in choleresis, of the concentration of potassium ions and cholates in the liver, and also of the cholinesterase activity in the serum and homogenates of the liver. Permeability of connective tissue structures of the liver and of the intercellular spaces of hepatocytes proved to fall. The influences of the hypothalamus on bile formation included a change in the functional activity of hepatocytes and of the production of a fluid fraction of the bile.
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PMID:[Mechanism of hypothalamic influences on bile formation]. 13 Sep 45

The effects of ionic strength, urea, calcium and fluorine ions, ouabain and cholinesterase inhibitors on the changes in the ionization equilibrium of an erythrocyte suspension under heating were studied. Proton release by erythrocytes was compared to a release of potassium ions and hemoglobin from the cells. The proton release under heating is mainly determined by the physico--chemical properties of superficial structures of erythrocytes and does not depend on the activity of cholinesterase, ATPase and glycolytic processes.
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PMID:[Changes in the ionization equilibrium of erythrocyte suspension under heating]. 13 48

In 30 workers being occupationally exposed to beryllium, examinations of biochemical indicators of liver efficiency were carried out: activity of alanine and asparagine aminotraspherase and basic phosphatases, cholinesterase, content of total protein and its fraction. Levels of electrolytes were determined: calcium, potassium, phosphorus, and magnesium. The above examinations were also carried out on 30 persons who have no contact with beryllium. The obtained results were subjected to statistical analysis. In 10 persons from the group exposed to beryllium one found lowering of the level of magnesium in blood serum, whereas in the control group the level of this electrolyte was correct in all persons. As to the results on the level of magnesium, in both groups high statistical significance was found (p less than 0,01). A dependence was found between the amount of workers and the lowered level of magnesium in blood serum and the duration of occupational exposure to beryllium. The comparison of the remaining results of examinations of both groups did not reveal any statistically significant differences or the differences were at the point of statistical significance.
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PMID:[Behavior of various biochemical indices of liver efficiency and of selected blood serum electrolytes in workers exposed to beryllium]. 19 75

It was shown that the phenomenon of inactivation of Na, K-ATPase of the non-purified fraction of the rat cortical synaptosomes under electroshock may be related to "modification" of the potassium active center of the enzyme. The anticonvulsant diazepam injected intramuscularly also inhibits Na, K-ATPase of the cerebral membranes. However, in subsequent electrical stimulation of the brain the drug activates Na, K-ATPase as compared to controls. Diazepam also abolishes clonic convulsions induced by electrical stimulation of the brain. At the same time it does not eliminate compensatory shifts in the activity of acetyl-cholinesterase of the rat cerebral and spinal synaptosomes, characteristic of electroshock. The results are discussed from the standpoint that inhibition of the activity of Na, K-ATPase of the nerve endings membranes may underlie the pathogenetic mechanism of the convulsive activity.
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PMID:[Na, K-ATPase activity of the meninges in electroshock and the action of the anticonvulsant agent, diazepam]. 21 51

The importance of serum cholinesterase activity in burned patients was evaluated in relation to anaesthesia. Anaesthesia included a repeated administration of suxamethonium. Thirty-two patients with an estimated area of burn between 3 and 72% were studied during 39 anaesthetic procedures. A statistically significant inverse correlation was found between serum cholinesterase activity and the apnoea period following intravenous suxamethonium. In patients with very low enzyme activity, apnoea periods of 10 to 25 min were observed. No correlation was found between the changes in serum potassium following suxamethonium and either the serum cholinesterase activity or the changes in Pco2 and pH. The most reliable parameters in predicting a dangerous increase in serum potassium following intravenous suxamethonium were shown to be 1) the time elapsed from burn injury to anesthesia and 2) the degree of burn injury. However, abnormal reactions to suxamethonium were seen as early as 9 days following injury, and rises in serum potassium to over 6 mmol/l were observed even in patients with a total burn surface of around 8%, i.e., less than the surface of one arm.
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PMID:Serum cholinesterase activity in burned patients. II: anaesthesia, suxamethonium and hyperkalaemia. 24 80

The effect of 4-methylthiophenyl dipropylphosphate (propaphos, organophosphorus insecticide) and 2-sec-butylphenyl-N-methylcarbamate (BPMC, carbamate insecticide) on the sensitivity to the effects of acetylcholine (ACh), carbachol (CCH) and nicotine was investigated on guinea-pig isolated ilea and atria. The response of these tissues to ACh was significantly enhanced in the presence of propaphos (3.3 x 10(-7) M) or BPMC (4.5 x 10(-6) M), while that to CCH was unaffected. The repeated administration of propaphos (5 mg/kg/day, p.o.) for 7 days had no effect on the contractile responses of guinea-pig ilea to potassium chloride. The responses of ilea and atria to ACh and nicotine were markedly increased by the administration of propaphos, and the values of ED50 and ED80 for their responses were significantly decreased. On the other hand, the response to CCH was decreased as was demonstrated by a significant increase in these values. Pretreatment with BPMC (25 mg/kg/day p.o., 7 days) significantly reduced the alteration in the responsiveness of the tissues to ACh, CCH and nicotine produced by the propaphos administration. The activity of cholinesterase (ChE) declined by 50--70% in blood and tissues from propaphos-treated animals, and its inhibition was significnatly reduced by the pretreatment with PBMC to 30--40%. These results indicate that changes in synaptic ChE activity, as reflected by the changes in ChE activity of blood and tissues, may be responsible for the alteration in sensitivity of ilea and atria to cholinergic agents produced by the repeated administration of propaphos and for the antagonism by BPMC.
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PMID:An alteration in sensitivity to cholinergic agents on guinea-pig ilea and atria after repeated administration of an organophosphate and an antagonism by a carbamate. 52 70

The effects of methylmercury chloride and other mercury compounds on cholinergic parameters were studied in vitro. Methylmercury chloride (MMC) and phenylmercury acetate inhibited choline acetyltransferase (ChA) with 20 microM of I50, and mercury nitrate (MN) with 100 microM of I50. All the three compounds had little effect on cholinesterase activity. MMC inhibited a high affinity choline uptake with 41 microM of Ki, as well as a low affinity choline uptake with 250 microM of Ki. MMC did not affect a spontaneous and potassium-stimulated ACh release from brain tissue slices incubated in eserinized Krebs-Ringer's solution up to the concentration of 100 microM. It was shown that the organic mercury compounds, such as methylmercury, were potent inhibitors of the choline uptake systems, as well as ChA activity.
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PMID:Effects of methylmercury chloride on various cholinergic parameters in vitro. 54 84

Karnovsky and Roots offer to use potassium ferricianide for coloured detecting the products of acetylcholine hydrolysis by cholinesterase. The method is based on the reduction of ferricianide to ferrocianide which forms with copper ions, present in the solution, unsoluble ferrocianide. Some properties of ferricianide ion, however, (stability, large size and great hydratation) make it difficult for the substance to penetrate the native cell membranes. The method by Karnovsky and Roots applied to laminated muscular tissue and to the rat nonfixed whole diaphragm, and to the sections from nonfixed tissue of the cat skeletal muscle verifies space isolation of ferricianide from the enzyme localized at the other side of cell membrane.
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PMID:[Use of potassium ferricyanide in histochemistry]. 64 58

The effects of treating adult wethers with 2 or 4 mg of coumaphos/kg of body weight each day for 6 days were investigated. The smaller dose produced a gradual decrease of erythrocyte acetylcholinesterase (AChE) activity (to maximum average reduction of approximately 45%), but without the appearance of signs of toxicosis. The larger dose appeared to be toxic. Treatment with the drug did not seem to alter significantly the anticholinesterase effects of a 2nd treatment made 6 weeks later. Coumaphos did not significantly affect serum activities of aspartate aminotransferase (glutamic oxalacetic transaminase) or isocitrate dehydrogenase (ICD) and concentrations of serum sodium and plasma calcium. A marked decrease in blood serum potassium and an increase in plasma magnesium occurred in all wethers that died after treatment with coumaphos, whereas appreciable changes did not occur in the survivors of the treatment given 6 weeks earlier. Treatment of sheep with an intravenous injection of the organophosphorous compound trichlorfon, insufficient to produce a significant effect on erythrocyte cholinesterase activity, produced additive effects with those of coumaphos.
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PMID:Repeated oral administration of coumaphos in sheep: effects on erythrocyte acetylcholinesterase and other constituents. 111 26


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