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

Enzymes capable of hydrolyzing esters of thiocholine have been assayed in extracts of Solanum melongena L. (eggplant) and Zea Mays L. (corn). The enzymes from both species are inhibited by the anti-cholinesterases neostigmine, physostigmine, and 284c51 and by AMO-1618, a plant growth retardant and they both have pH optima near pH 8.0. The enzyme from eggplant is maximally active at a substrate concentration of 0.15 mM acetylthiocholine and is inhibited at higher substrate concentrations. On the basis of this last property, the magnitude of inhibition by the various inhibitors, and the substrate specificity, we conclude that the enzyme from eggplant, but not that from corn, is a cholinesterase.
 ...
PMID:Cholinesterases from plant tissues. VI. Preliminary characterization of enzymes from Solanum melongena L. and Zea mays L. 0 67

The intrinsic innervation of the lungs (right and left) has been studied by the cholinesterase technique, considering the effect of various pH, incubation periods and temperatures. Cholinergic innervation dominated. The peribronchial ganglia, large, medium-sized and irregular-shaped, rounded and small, showed a positive cholinesterase reaction. Maximum ChE activity was noticed in the bronchi and their branches and on the periphery of the alveoli.
 ...
PMID:Neurohistological and histochemical observations on the lung of Rattus rattus rufescens (Indian black rat). 0 62

The thiocholine method for the histochemical detection of cholinesterases according to Karnovsky-Roots was adapted for unfixed cryostat sections by addition of the agar solution to the incubation mixture and by using the semipermeable membrane interposed between the section and the incubation medium. The procedure prevents the leakage of the enzyme activity of the section and is suitable for tissues where the cholinesterase activity is low.
 ...
PMID:The possibilities and limitations of membrane methods for the histochemical demonstration of cholinesterases. 0 69

Experiments in vitro demonstrated that a thermostatic treatment of an aqueous chlorophos solution at 38 degrees is attended by its increased cholinesterase activity. The speed of the process is much higher in an alkaline medium. A joint incubation of chlorophos with the TMB-4 reactivator of pH of 7.5 and 38 degrees not only fails to result in decomposition of the poison, but on the contrary, tends to speed up the progressive accretion of the inhibitory properties of this organophosphorus compound. The author considers the data obtained as one of the proofs pointing to the formation during direct interaction of TMB-4 with chlorophos or the product of its transformation of a stable complex appearing to be a powerful anticholinesterase agent.
 ...
PMID:[Heightened anticholinesterase activity of chlorophos in its interaction with the TMB-4 reactivator in vitro]. 0 34

Gamma-glutamyl transpeptidase activity in kidney homogenates, aspartate and alanine aminotransferase activities in liver homogenates, and cholinesterase activity in brain homogenates were determined in nonpregnant and pregnant guinea pigs exposed to absorption through the skin of the epoxy resin triethylenetetramine. Elevated activity of gamma-glutamyl transpeptidase in the kidneys of pregnant animals, and aspartate aminotransferase in the liver of nonpregnant guinea pigs were observed.
 ...
PMID:Influence of industrial toxic compounds on pregnancy. VI. Some tissue enzymes in pregnant guinea pigs exposed to the action of triethylenetetramine. 0 46

Microwave irradiation of 6 kw at 2450 MHz for 300 msec was sufficient to completely inactivate mouse brain cholinesterase and choline acetyltransferase. After this method of sacrifice, the acetylcholine contents of mouse brain regions, given in nanomoles per gram, were found to be: striatum, 81; medulla-pons, 44; diencephalon-midbrain, 34; hippocampus, 31; cerebral cortex, 26; and cerebellum, 17. Sodium pentobarbital caused a dose-dependent increase in whole brain acetylcholine. A maximal increase of 81% in whole brain was seen at 15 minutes with 80 mg/kg of sodium pentobarbital. The increase in acetylcholine after sodium pentobarbital treatment was not caused by anoxia from respiratory depression or by hypothermia. All brain regions except the cerebellum exhibited an increase in acetylcholine after pentobarbital treatment. Fifteen minutes after treatment, cerebellar acetylcholine was significantly decreased. However, at the time when half of the animals had regained the righting reflex, the unconscious mice showed an increase in cerebellar acetylcholine which was statistically significant as compared to control. The relative accumulation rate of acetylcholine calculated for cerebral cortex and hippocampus was higher than that for striatum although the absolute rate of accumulation of ACh was higher in the striatum. Thus, after sodium pentobarbital treatment, the cerebral cortex and hippocampus exhibit a greater cholinergic response than the striatum.
 ...
PMID:Use of 300-msec microwave irradiation for enzyme inactivation: a study of effects of sodium pentobarbital on acetylcholine concentration in mouse brain regions. 0 94

The multiple cholinesterase activities in canine platelets have been investigated. Platelets were homogenized by rapid decompression under nitrogen, glass tube/Teflon pestle, and glycerol lysis techniques. Rapid decompression under nitrogen technique was found to be the most efficient and gentle method for cell disruption. Homogenates were subfractionated using sodium diatrizoate density gradients. Marker enzyme assays and pulse labeling experiments with 5-hydroxyl[14C] tryptamine and [125I] thrombin on prepared subcellular fractions confirmed that the soluble, plasma membrane and the granule-1 fractions were all in reasonably pure form. Furthermore, labeling of the plasma membrane with [125I] thrombin is cited as the first successful attempt at attaining significantly bound marker for this structure. Cholinesterase activity distributions measured in these fractions indicated that about 30% of the activity was present in the plasma membrane, 50% in granule-1 and 5% in soluble fractions. Kinetic data of cholinesterase activities obtained from intact platelets, plasma membrane preparations and platelet release supernatants indicated that they are strikingly similar.
 ...
PMID:The subcellular distribution and partial characterization of cholinesterase activities of canine platelets. 0 47

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.
 ...
PMID:The effect of cholinesterase inhibitors on the antimuscarinic effect of hemicholinium-3 (HC-3) in the rat. 0 55

Acetylsecohemicholinium No. 3 (AcHC-3), the acetate of the open ring (seco form of hemicholinium No. 3, HC-3) hydrolyzes in vitro to the hemiacetal HC-3 at pH values above 9, a temperature-dependent conversion illustrated by ultraviolet spectral shifts from 305 to 257 mmu, and to a limited extent by certain esterases as measured by manometric analysis. An LD50 of 125 mug/kg for a neutral solution of AcHC-3 was decreased to 78.3 mug/kg (the LD50 of HC-3) upon being made basic. Prolonged treatment of mice with LD10-20 doses of AcHC-3 was associated with decreased fatty acid oxidation in the liver and resulted in infiltration of fat into hepatic cells, a reaction preventable by treatment with small doses of choline (10 mg/kg). AcHC-3 causes neuromuscular and autonomic ganglionic blockade, cholinesterase inhibition, and in vitro inhibition of acetylcholine (ACh) synthesis. These actions, although HC-3-like, appear to be due to AcHC-3 rather than HC-3 since neither cholinesterase inhibition nor hepatic ligation altered the neuromuscular blocking actions of AcHC-3. In addition to its HC-3-like properties, AcHC-3 consistently produced a transient increase in twitch height of gastrocnemius muscle before blockade and was dose-responsive in depressing blood pressure and in eliciting contractions of the isolated guinea pig ileum. AcHC-3 is both a cholinomimetic (depresses arterial blood pressure, decreases heart rate and increases ileal contractions) and a competitor of acetylcholine. That is, in most preparations tested, AcHC-3 at lower concentrations has as much intrinsic activity as ACh and at somewhat higher concentrations competitively blocks the responses to ACh. These cholinomimetic actions may be due to the presence of two ACh moieties on the AcHC-3 molecule which attach to cholinergic receptor sites. Also noted was an action of AcHC-3 that seems to be peculiar to the secohemicholiniums, namely, the potentiation of catechloamines.
 ...
PMID:Acetylsecohemicholinium: chemical and pharmacological evaluation of an open-ring hemicholinium. 0 97

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.
 ...
PMID:A comparison of the cholinesterases of an oyster (Crassostrea virginica) and a clam (Macrocallista nimbosa). 1 Mar 39


1 2 3 4 5 6 7 8 9 10 Next >>