Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 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 effect of galanthamine, tacrine, and oxazyl (ambenomum) on human red cells acetylcholinesterase phosphorylation by armine and Gd-42 (o-ethyl-s-beta-ethylthioethyl ester of methylthiophosphinic acid) was studied. In the presence of galanthamine phosphororganic inhibitors interacted only with the active center of the enzyme, the anionic site of which was not occupied by the reversible inhibitor. Tacrine and oxazyl decreased the reactivity of the free enzyme and the rate of its phosphorylation.
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PMID:[Effect of reversible inhibitors on the reaction capacity of functional portions of the active center of acetylcholinesterase]. 70 73

Armine treatment of mice against the background of preliminary galanthamine injection diminished the inhibition of the acetylcholinesterase of the brain caused by a reversible inhibitor. This effect was connected with the acetylcholine accumulation and the displacement by it of galanthamine from the active centres of the enzyme. Thus, a competitive character of galanthamine-acetylcholinesterase interaction was shown in vivo.
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PMID:[Galanthamine interaction with mouse brain acetylcholinesterase in in vivo experiments]. 95 43

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 inhibiting compounds were separated by micro-column liquid chromatography in the mobile phase containing the natural substrate acetylcholine. A home-made packed bed microbioreactor system containing immobilized enzyme acetylcholinesterase (ACHE) in human red blood cell membrane and choline oxidase (CHO) from alcaligenes was used for the post-column conversion of acetylcholine to hydrogen peroxide which was detected by an electrochemical detector. The inhibition effect of the solutes caused a decrease in the acetylcholinesterase activity, a decrease in the formation of hydrogen peroxide and also a decrease in the response corresponding to the concentration of the solutes. The rate of the enzyme regeneration was also recorded. The micro-system was compared with a conventional LC system comprising commercially prepared enzyme reactor. The stability of the enzymes is at least 3 weeks at ambient temperature. The limit of detection depends on biological activity of inhibition and for galanthamine was 1 pmol.
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PMID:Indirect detection of anti-acetylcholinesterase compounds in microcolumn liquid chromatography using packed bed reactor with immobilized human red blood cell acetylcholinesterase and choline oxidase. 129 99

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

Amnesia can be induced in rats in the passive avoidance paradigm by administration of scopolamine, a central muscarinic receptor antagonist. Tacrine or galanthamine, inhibitors of acetylcholinesterase, given in conjunction with scopolamine partially reversed the scopolamine-induced deficit in passive avoidance performance. Four so-called cognitive enhancers, all widely used for the treatment of the symptoms associated with mental aging, cerebral insufficiency and senile memory disorder, were investigated in this paradigm. Piracetam, an extract of Ginkgo biloba, dihydroergocristine and a combination of raubasine with dihydroergocristine, all attenuated the amnesia induced by scopolamine. In contrast, nicergoline had no significant effect. Raubasine alone also failed to significantly attenuate scopolamine-induced amnesia, although some doses of raubasine had a non-significant tendency (P less than 0.10) to reduce the amnesia.
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PMID:Effects of four non-cholinergic cognitive enhancers in comparison with tacrine and galanthamine on scopolamine-induced amnesia in rats. 173 91


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