Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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 effect of hemicholinium-3 (HC-3) on responses of the rat isolated bladder and ileum to acetylcholine and carbachol was investigated in the absence and presence of a number of anticholinesterases. Responses of the bladder to acetylcholine were potentiated by DFP, edrophonium, BW284C51 and physostigmine but were unaffected by the specific butyrylcholinesterase inhibitor iso-OMPA. Responses to carbachol were not potentiated by the anticholinesterases. HC-3 (1.7 X 10(-4) M) inhibited responses to carbachol without affecting those to acetylcholine. In the presence of physostigmine or DFP responses to acetylcholine were inhibited by HC-3 but no such inhibition was observed in the presence of BW284C51, edrophonium or iso-OMPA or a combination of the latter two anticholinesterases. Responses to carbachol were also inhibited to a greater extent in the presence of DFP. In the ileum, responses to acetylcholine were increased in the presence of DFP, edrophonium and physostigmine but were unaffected by iso-Ompa. responses to carbachol were not increased by any of the anticholinesterases. HC-3 (2.8 X 10(-4) M) inhibited responses to both acetylcholine and carbachol in the ileum and the degree of inhibition was not significantly altered by the presence of any of the anticholinesterases used. Although a weak anticholinesterase, HC-3 was also found to decrease the inhibitory action of physostigmine on the hydrolysis of acetylcholine by homogenates of rat ileum. A similar effect was noted with DFP but not with edrophonium. The results obtained do not support a prejunctional action for HC-3 in antagonizing responses to carbachol. It is concluded that in addition to an inhibitory action on the post-junctional muscarinic receptor HC-3 may interfere with the anticholinesterase activity of some cholinesterase inhibitors such as physostigmine and DFP but not edrophonium.
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PMID:The effect of cholinesterase inhibitors on the antimuscarinic effect of hemicholinium-3 (HC-3) in the rat. 0 55

Cholinesterase activities in the hearts and ganglia of an oyster (Crassostrea virginica) and a venerid clam (Macrocallista nimbosa) were measured and compared. Tissue extracts were partially purified by ammonium sulfate fractionation followed by gel column chromatography. Enzymatic activity was assayed spectrophotometrically; substrates were acetyl-, butyryl-, and propionylthiocholine (ATC, BTC, PTC). Kinetic constants characterizing each enzyme were derived. At all substrate concentrations, the hydrolysis rates of both clam enzymes were in the order: BTC greater than PTC greater than ATC. With oyster enzymes the ranking was ATC greater than or equal to PTC greater BTC. The specific activities of oyster heart and ganglion enzymes were similar. In contrast, clam ganglion extracts were 75-100 times more active than clam heart extracts and, with any substrate, had greater activity than either oyster enzyme. All enzyme preparations proved to be homogeneous on the bases of constant substrate activity ratios in successive column fractions, and of intermediate velocities with mixed substrates. Six cholinesterase inhibitors were tested. The specific acetylcholinesterase antagonist, B.W. 62C47, WAS MUCH MORE EFFECTIVE AGAINST OYSTER ENZYMES, WHILE THE SPECIFIC ANTIBUTYRYLCHOLINESTERASE, ISO-OMPA, almost totally inhibited calm enzyme activity, but had little effect on oyster. Eserine was the most effective inhibitor of both enzymes. In conclusion, the enzymes in oyster tissues are acetylcholinesterases, while clam enzymes are butyrylcholinesterases. Nevertheless, clam ganglion esterase is sifficiently active to hydrolyze the physiological substrate, acetylcholine. These results explain the long-observed differences in isolated heart pharmacology between ostreid and venerid bivalves.
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PMID:A comparison of the cholinesterases of an oyster (Crassostrea virginica) and a clam (Macrocallista nimbosa). 1 Mar 39

Specific and non specific cholinesterase activities were demonstrated in the ABRM of Mytilus edulis L. and Mytilus galloprovincialis L. by means of different techniques. The results were found identical for both species: neuromuscular junctions "en grappe"-type scarely distributed within the ABRM, contain AChE. According to the histochemical inhibition tests, (a) the eserine inhibits AChE activity of the ABRM with a level of 5-10(-5) M or higher, (b) the ChE non specific activities are inhibited by iso-OMPA level between 5.10(-5) to 10(-4) M. The histo- and cytochemical observations were completed by showing the existence of neuromuscular junctions containing small clear vesicles: they probably are the morphological support for ACh presence. Moreover, specific and non specific ChE activities were localized in the glio-interstitial cells. AChE precipitates were developed along the ABRM sarcolemma, some muscle mitochondria and in the intercellular spaces remain enigmatic.
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PMID:[Innervation of the anterior byssus retractor muscle (ABRM) in Mytilus edulis L. and in Mytilus galloprovincialis Lmk. V. Cytochemical localization of cholinesterase activities (author's transl)]. 64 Aug 63

The properties of a cholinesterase from mucosal cells of rat intestine have been characterized. The enzyme was identified as butyrylcholinesterase because it was more sensitive to iso-OMPA (IC50 = 1.0 x 10(-6) M) than to BW284C51 (IC50 = 5.5 x 10(-5) M) and was not inhibited by substrate excess. It displayed a higher affinity for acetylthiocholine than for butyrylthiocholine. A major molecular form was observed sedimenting at 5.9 S. Two other minor molecular forms were identified as a hydrophilic tetramer (G4, sedimenting at 10.5 S) and a monomer (G1, sedimenting at 4.3 S). The 5.9 S component was referred to as "G" form (G for globular) and not "G2" as usual dimers for the following reasons: (i) the G form was unaffected by the reducing agents, beta-mercaptoethanol and dithiothreitol, which converted disulfide-linked dimers of acetylcholinesterase into monomers, (ii) the G form was shifted from 5.9 to 3.4 S when the sucrose gradient contained Triton X-100. This value of 3.4 S (in Triton X-100) appeared too low for a typical G2 form. The shift in the S value was partly reversible: the 3.4 S form resedimented at 5.2 S in the absence of detergent. The behavior of the G form in sucrose gradients indicated that it was amphiphilic. This was confirmed in nondenaturing electrophoreses and also by quantitative binding of the G form to octyl-Sepharose. The hydrophobic domain of the G form was not a glycolipid, as shown by its insensitivity to Bacillus thuringiensis phosphatidylinositol-specific phospholipase C and its nonaggregating properties in the absence of nondenaturing detergent.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Amphiphilic forms of butyrylcholinesterase in mucosal cells of rat intestine. 142 Feb 1

Torpedo acetylcholinesterase (AcChoEase, EC 3.1.1.7) and human butyrylcholinesterase (BtChoEase, EC 3.1.1.8), while clearly differing in substrate specificity and sensitivity to inhibitors, possess 53% sequence homology; this permitted modeling human BtChoEase on the basis of the three-dimensional structure of Torpedo AcChoEase. The modeled BtChoEase structure closely resembled that of AcChoEase in overall features. However, six conserved aromatic residues that line the active-site gorge, which is a prominent feature of the AcChoEase structure, are absent in BtChoEase. Modeling showed that two such residues, Phe-288 and Phe-290, replaced by leucine and valine, respectively, in BtChoEase, may prevent entrance of butyrylcholine into the acyl-binding pocket. Their mutation to leucine and valine in AcChoEase, by site-directed mutagenesis, produced a double mutant that hydrolyzed butyrylthiocholine almost as well as acetylthiocholine. The mutated enzyme was also inhibited well by the bulky, BtChoEase-selective organophosphate inhibitor (tetraisopropylpyrophosphoramide, iso-OMPA). Trp-279, at the entrance of the active-site gorge in AcChoEase, is absent in BtChoEase. Modeling designated it as part of the "peripheral" anionic site, which is lacking in BtChoEase. The mutant W279A displayed strongly reduced inhibition by the peripheral site-specific ligand propidium relative to wild-type Torpedo AcChoEase, whereas inhibition by the catalytic-site inhibitor edrophonium was unaffected.
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PMID:Conversion of acetylcholinesterase to butyrylcholinesterase: modeling and mutagenesis. 143 84

We studied the effect of inhibition of pseudocholinesterase by a specific pseudocholinesterase inhibitor, tetraisopropyl pyrophosphoramide (ISO-OMPA) on the cardiorespiratory toxicity of intravenously injected cocaine in rats. Group 1 rats received ISO-OMPA subcutaneously, whereas group 2 rats received saline placebo subcutaneously. Thirty minutes later, rats were anesthetized with 40 mg/kg of sodium pentobarbital intraperitoneally and were then given 10 mg/kg (least toxic dose) cocaine intravenously. Thirty minutes after the first injection of cocaine, about half of the rats that survived from each group were given 12 mg/kg cocaine (low toxic dose) intravenously, and the other half was given 13.5 mg/kg cocaine (high toxic dose) intravenously. Five minutes after each injection, rats were classified as either survivors or fatalities. In group 1 (ISO-OMPA treated), five of 29 (17%) rats that received 10 mg/kg cocaine, two of 11 (19%) that received 12 mg/kg cocaine, and three of 13 (24%) that received 13.5 mg/kg cocaine died of cardiorespiratory toxicity. In group 2 (saline treated), two of 29 (7%) that received 10 mg/kg cocaine, six of 12 (50%) that received 12 mg/kg cocaine, and 10 of 15 (67%) that received 13.5 mg/kg cocaine died of cardiorespiratory toxicity (p less than 0.03). Pseudocholinesterase activity (mean +/- SEM) of groups 1 and 2 were 0.6 +/- 0.2 and 7.3 +/- 0.7 units, respectively (p less than 0.01). Our results show that rats with lower pseudocholinesterase activity had lower fatality rates than rats with higher pseudocholinesterase activity.
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PMID:Inhibition of pseudocholinesterase activity protects from cocaine-induced cardiorespiratory toxicity in rats. 847 99

The phylo- and ontogenetically related enzymes butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) are expressed consecutively at the onset of avian neuronal differentiation. In order to investigate their possible co-regulation, we have studied the effect of highly selective inhibitors on each of the cholinesterases with respect to their expression in rotary cultures of the retina (retinospheroids) and stationary cultures of the embryonic chick tectum. Adding the irreversible BChE inhibitor iso-OMPA to reaggregating retinal cells has only slight morphological effects and fully inhibits BChE expression. Unexpectedly, iso-OMPA also suppresses the expression of AChE to 35%-60% of its control activity. Histochemically, this inhibition is most pronounced in fibrous regions. The release of AChE into the media of both types of cultures is inhibited by iso-OMPA by more than 85%. Control experiments show that AChE suppression by the BChE inhibitor is only partially explainable by direct cross-inhibition of iso-OMPA on AChE. In contrast, the treatment of retinospheroids with the reversible AChE inhibitor BW284C51 first accelerates the expression of AChE and then leads to a rapid decay of the spheroids. After injection of BW284C51 into living embryos, we find that AChE is expressed prematurely in cells that normally express BChE. We conclude that the cellular expression of AChE is regulated by the amount of both active BChE and active AChE within neuronal tissues. Thus, direct interaction with classical cholinergic systems is indicated for the seemingly redundant BChE.
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PMID:Chicken retinospheroids as developmental and pharmacological in vitro models: acetylcholinesterase is regulated by its own and by butyrylcholinesterase activity. 162 98

Human pancreas contains two cholinesterase isoenzymes: acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). In the present study, binding potency of two organophosphates for human cholinesterases were compared by the Ellman method. Echothiophate was found to have much greater potency than iso-OMPA for both cholinesterases. Using Karnovsky histochemical stains on human pancreatic tissue, the same results were confirmed. Dose-response studies with acetylcholine were done on viable pancreas fragments from nine human donors, without pancreatic disease (group I). Cold-preservation time was less than 30 h. Pancreas was minced into fragments, after the technique of Scheele and Palade, placed in Eagle's medium, and gassed with O2. Amylase release was measured by the Phadebas Method and corrected for basal release. There was a dose-dependent response to acetylcholine at 1 and 2 h, with a shift in peak amylase release to the left, when fragments were preincubated in 10(-4) M echothiophate. This indicated a 100-fold increase in sensitivity to acetylcholine. In three patients with chronic pancreatitis (Group II), there were variable patterns of response of amylase release to acetylcholine, and higher basal outputs. In Group III, prolonged storage conditions of over 40 h were tested for 4 pancreas donor tissues. There was no response to acetylcholine. These studies show that for up to 30 h cold storage, fragments of pancreas from human organ donors respond to acetylcholine in dose-dependent manner. An organophosphate, echothiophate (10(-4) M) which inhibits both cholinesterases, increases pancreatic sensitivity to acetylcholine, and these results are similar to findings from canine pancreas fragments, which also showed increased sensitivity.
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PMID:Organophosphate increases the sensitivity of human exocrine pancreas to acetylcholine. 171 83

The distribution pattern of cholinesterase activity in the basal forebrain region was examined in five human brains without any history of neurologic or psychiatric disorders. Complete sets of serial sections allowed a three-dimensional reconstruction of this region. The intensity grading and the distribution pattern of the specific and non-specific cholinesterase activity was depicted diagramatically. The distribution pattern of cholinesterase activity in the supracommissural striatum demonstrated the well-known striosomal configuration, particularly in the head of the caudate nucleus. Within this nucleus caudatus the striosomes appeared connected with a subventricular zone of low acetylcholinesterase-activity. Bands of very high activity could be demonstrated from the dorsolateral and ventral areas of the caudate nucleus to the lateral border of the putamen and the commissural and subcommissural division of the ventral striatum. The distribution pattern of cholinesterase activity in the subcommissural region showed very close correlation to the cytomorphological subdivisions of the striatum as defined by Brockhaus (1942). In addition to his topographic description it was possible to define the tuberculum olfactorium and several subdivisions of the interstitial nucleus of the stria terminalis. The inhibition of non-specific esterase activity by ISO-OMPA in the globus pallidus allowed distinction between striatal and pallidal components. Three-dimensional reconstructions of the terminal islands revealed several types, which were named according to their topography as insulae substriatales, -subventriculares, -olfactoriae, -magnae, and -interstitiales. Characteristically, the core of these islands consisted of clusters of tightly packed, extremely high acetylcholinesterase-positive cells. Cholinesterase activity of the surrounding rim region ranged from negative to strongly positive depending on the position and type of the island. The findings suggest that the islands represent derivatives of the fundus striati region as defined by Brockhaus and are connected to the dorsal striatum by means of cellular bridges.
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PMID:[Cholinesterase activity in the human striatum with special consideration of the terminal islands]. 177 33

The regulation of acetylcholine (ACh) lifetime by acetylcholinesterase (AChE, EC 3.1.1.7) and butyrylcholinesterase (BuChE, EC 3.1.1.8) was evaluated in vitro in canine tracheal smooth muscle preparations. Selective inhibition of AChE by low concentrations of 1,5-bis(N-allyl-N,N-dimethyl-4-ammoniumphenyl)-pentane-3-one dibromide (BW 284C51) led to increases in the amplitude and half-relaxation time of contractions elicited by electric field stimulation. Maximal responses were observed in the presence of 10(-6) M BW 284C51, where the amplitude and half-relaxation time were increased by 84 and 198%, respectively. Higher concentrations of BW 284C51, on the other hand, depressed the amplitude and shortened the decay of electric field stimulation-induced contractions by a mechanism involving blockade of muscarinic receptors. Selective inhibition of BuChE by tetraisopropylpyrophosphoramide (iso-OMPA) led to monotonic increases in the electric field stimulation amplitude and duration. These alterations were less marked than those observed in the presence of BW 284C51. Co-application of BW 284C51 (10(-5) M) and iso-OMPA (10(-5) M) resulted in a 1330% prolongation in the decay of electric field stimulation-induced contractions and the development of a sustained contracture. Such contractures were not observed with either inhibitor alone at any concentration tested. The results indicate that both hydrolytic enzymes are involved in the regulation of ACh lifetime at the canine tracheal neuroeffector junction with AChE exerting the more prominent role. The finding that BuChE co-regulates ACh lifetime in canine trachealis muscle demonstrates a functional role for this enzyme.
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PMID:Regulation of acetylcholine hydrolysis in canine tracheal smooth muscle. 181


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