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)

In clinical anaesthesia, galanthamine hydrobromide (Nivalin), an alkaloid of galanthus nivalis (common snowdrop) is used to reverse the neuromuscular blocking effect of curare-type muscle relaxants. A comparative study of the inhibition by galanthamine of acetylcholinesterase (AChE; PH 7,2; substrate; acetylthiocholine) and of pseudocholinesterase (ChE; ph 7,7; substrate: butyrylthiocholine) was carried out by means of a colorimetric assay technique at 25 degrees C. AChE (pI50 = 5.5; Ki = 5.2 X 10(-8) M) has an approximately 100-fold higher affinity to galanthamine than has ChE (pI50 = 3.7; Ki = 2.9 X 10(-6) M). The kinetic analysis of the inhibition which is instantaneously reversible upon dilution revealed a pure competitive mechanism of action for both enzymes. Supported by a calculation of the change in free binding energy (AChE: delta F = 9.9 kcal X mole-1; ChE: delta F = -7.6 kcal X mole-1), galanthamine is thought to decrease the rate of hydrolysis by a reversible binding to the anionic site of the active centre ("prosthetic inhibitor") thus impairing the formation of the enzyme-substrate complex.
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PMID:[On the molecular mechanism of action of galanthamine, an antagonist of nondepolarizing muscle relaxants (author's transl)]. 13 19

The kinetics of inhibition of the human red blood cell cholinesterase with galanthamine tacrine and oxazyl (ambenonium) and the effect of these drugs on chick, mouse, cat and rat blood plasma enzyme activity was studied. Galanthamine proved to bind with acetylcholinesterase in the anionic areas of the catalytic centres, oxazyl interacted in the area of the allosteric anionic site, and tacrin interacted with the hydrophobic areas of the enzyme.
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PMID:[Interaction of reversible inhibitors with the catalytic centers and allosteric sites of cholinesterases]. 102 94

The capacity of reversible inhibitors--galanthamine and tacrine--to protect the cholinesterase of rat and mouse brain from the thermal denaturation with the action of the temperature of 56 and 58 degrees C was revealed. The protective action was also noted when the reversible inhibitors decreased the activity of the enzyme. It appeared that with galanthamine the cholinesterase resistance to the thermal action was greater than with the action of tacrine.
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PMID:[Effect of reversible inhibitors on the thermal denaturation of cholinesterases]. 119 68

In vitro tests set up to compare the anticholinesterase, cholinomimetic, cholinopotentiating and cholinolytic activity of 6 reversible cholinesterase inhibitors furnished grounds for an inference that all these agents produce an anticholinesterase effect which determines the qualitative specificity of their action. This specificity has been demonstrated in experiments on cats and rabbits. Some of the drugs (oxazyl) exert a practically elective effect on the H-cholinoreactive muscle systems, whereas others (eserin) act in a similar manner on the M-cholinoreactive systems of the intestines. The action of proserine and galanthamine os of a less selective nature.
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PMID:[Comparison of anticholinesterase activity and the effectiveness of anticholinesterase substances]. 121 23

Experiments set up on mice demonstrated that galanthamine, hydrobromide, physostymine salicilate and iodomethylate produce a fall of the renal temperature, the hypothermal effect being proportional to the suppression of the cerebral cholinesterase. Anticholinergics benactyzine and atropine were largely capable of preventing hypothermia produced by the introduction of galathamine hydrobromide, the latter increasing the resistance of the animals to the action of high temperature.
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PMID:[Mechanism of the hypothermic action of reversible cholinesterase inhibitors]. 122 97

The action of galanthamine (GAL), a cholinesterase inhibiting substance, on resting EEG and on flash visual evoked potentials (VEPs) was tested in 9 healthy subjects. Alpha power was increased significantly in 4 of 8 subjects after the infusion of 10 mg, which provided a median inhibition of 47% of acetylcholinesterase in erythrocytes. Mean alpha frequency and peak alpha frequency decreased significantly in 5 of the 8 subjects by 0.22-0.98 Hz. Alpha power increase and alpha frequency decrease were not accompanied by changes in theta power. The amplitudes of the late components of the flash VEP were increased in 8 of 9 subjects receiving doses of 10-35 mg of GAL, while the early components remained unaffected. Increase of late VEP components was significantly correlated with the strength of cholinesterase inhibition. The synchronizing effect of GAL in these healthy volunteers obviously contrasts with the known desynchronizing effect of physostigmine in animal experiments.
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PMID:Effect of the cholinesterase inhibiting substance galanthamine on human EEG and visual evoked potentials. 137 52

18 patients who had fulfilled the NINCDS-ADRDA criteria for "possible AD" took part in a clinical study to evaluate the effect of the cholinesterase inhibitor Galanthamine, 30 mg/day. Neuropsychological und social parameters were rated. This open clinical pilot-study showed no statistic significant change in neuropsychological test-results. However after 1 year treatment 6 patients are still taking the drug. According to their care-persons there was a positive changes in competence of everyday-routine and/or in the emotional situation.
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PMID:Galanthamine treatment in Alzheimer's disease. 175 53

The influence of the cholinesterase inhibitor galanthamine (Nivalin), of the cholinergic agonist oxotremorine, and of the muscarinic cholinergic antagonist scopolamine on the retention-improving effect of angiotensin II (AT II) was studied in male Wistar rats trained and tested for retention (24h later) using two paradigms: two-way active avoidance (shuttle-box) and passive (step-through) avoidance. AT II and the cholinergic agonists, administered together potentiated their retention-improving effects, while scopolamine abolished the memory effect of AT II. It is suggested that brain cholinergic neurotransmission participates in the mechanisms of the memory-facilitating effect of AT II.
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PMID:Cholinergic influence on memory facilitation induced by angiotensin II in rats. 196 94

Catalytic properties of human blood erythrocyte acetylcholinesterase and horse blood serum butyrylcholinesterase immobilized and nonimmobilized in the gelatin membrane have been comparatively studied. Cholinesterase immobilization induces an increase in the Michaelis constant value and a decrease in the maximum rate value in reactions of enzymic hydrolysis of thiocholine ethers, but exerts no effect on these kinetic parameters in case of enzymic hydrolysis of indophenylacetate. The effect of reversible inhibitors: galanthamine, N-methyl-4-piperidinyl benzylate and 1,2,3,4-tetrahydro-9-aminoacridine (tacrine), as well as of irreversible inhibitors: O-ethyl-O-(4-nitrophenyl)ethyl phosphonate (armin), diisopropyl fluorophosphate (DFP), O,O-diethyl-O-(4-nitrophenyl) phosphate (paraoxon) and O,O-dimethyl-O-(2,2-dichlorovinyl) phosphate (DDVP) on immobilized cholinesterases is weaker as compared with the effect on nonimmobilized enzymes. The results obtained are discussed for the effect of immobilization on the catalytically active enzyme surface.
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PMID:[Catalytic properties of cholinesterases immobilized in a gelatin membrane]. 208 92

We investigated the inhibition of human cholinesterases by galanthamine, an alkaloid of the common snowdrop (galanthus nivalis). In vitro, the compound showed potent enzyme inhibition and 50-fold selectivity for acetylcholinesterase (EC 3.1.1.7) as opposed to butyrylcholinesterase (EC 3.1.1.8). There was no difference between enzyme inhibition by galanthamine in whole blood and separated fractions of plasma and erythrocytes. We conclude that galanthamine does not accumulate in large amounts in red blood cells. In vivo, administration of galanthamine in a healthy volunteer and in a patient who underwent long-term treatment confirmed the selectivity of galanthamine for acetylcholinesterase.
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PMID:Selective inhibition of human acetylcholinesterase by galanthamine in vitro and in vivo. 235


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