Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An ultrastructural analysis was made on acetylcholinesterase (AChE) localization in the optic tectum of two teleosts, the goldfish and the catfish. Electron microscope histochemistry reveals several details on synthesis, distribution and possible sites of utilization of the enzyme in the different tectal layers. The results show that AChE is synthesized by all the neuronal types present in the optic tectum. The final localization of the enzyme is the result of its synthesis in cell bodies, its storage and transport along dendrites and its release in extracellular spaces. The differences in AChE localization between the two teleosts examined mainly derive from differential enzyme release in the corresponding layers of the optic tectum. Cholinergic synapses cannot be precisely identified by means of AChE histochemistry, but the layers in which maximum release of enzyme in the extracellular spaces occurs most likely correspond to areas where cholinergic mechanisms are operating. In this connection some interesting differences of AChE localization in the superficial tectal layers (stratum marginale, stratum opticum and stratum fibrosum et griseum superficiale) are discussed. Electron microscopic histochemistry of AChE confirms its usefulness in better understanding some links between the anatomical and functional organization of complex neural structures.
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PMID:Electron microscope histochemistry of acetylcholinesterase distribution in the optic tectum of teleosts. 9 27

Studies have been made on structural and catalytic peculiarities of acetylcholinesterase (AChE) in the large hemispheres of newborn, 1-month and adult rabbits. During postnatal life, no changes were found in the structure of active surface of the enzyme, although differences were revealed in macromolecular organization and sensitivity of the enzyme to allosteric ligands. It is suggested that structural organization of AChE in postnatal ontogenesis becomes more complex which provides for more precise regulation of its activity.
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PMID:[The structural catalytic characteristics of brain acetylcholinesterase in rabbit postnatal ontogeny]. 9 40

The share of external acetylcholinesterase (AChE) has been determined in different brain structures of maturely and immaturely born rodents. It was found that in maturely born animals (guinea pigs) the share of external AChE in all the studied brain structures is the same in newborn and adult individuals. In immaturely born animals (albino rats) the share of external AChE to the moment of birth is significantly higher as that in adult organisms. During the development of the brain, the share of the external enzyme decreases, the decrease being more evident in the forebrain. It is suggested that this decrease is associated with fixation of the enzyme to the membrane, which is indicated in particular by the experiments with detergents.
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PMID:[External brain acetylcholinesterase in the ontogeny of precocial and altricial rodents]. 9 39

The influence of cold exposure at 4 degrees C for different periods of time (from 12 h to 42 days) on the allosteric inhibition by F- of the rat erythrocyte membrane-bound acetylcholinesterase from rat fed a corn oil diet was studied. The cold exposure decreased the values of the Hill coefficient n from 1.6 to 1.0. When the cold-exposed rat was transferred from the cold environment to 23 degrees C, the values of n reached the control values. The factors that play in the allosteric desensitization phenomenon were characterized as L-triiodothyronine, L-thyroxine, and thyrotropin. The relationship betwen changes in the values of n and physiological concentrations of thyroid hormones and thyrotropin in cold-exposed rat is shown. Thyrotropin showed a facilitatory action on the blocking action of thyroxine on the triiodothyronine effect. The intravenous injection of thyrotropin-releasing hormone (TRH) yields confirmatory results for this regulatory mechanism since the values of n for acetylcholinesterase shifted as predicted.
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PMID:Effect of cold exposure on rat erythrocyte membrane-bound acetylcholinesterase. Role of thyrotropin in the thyroid hormones interplay. 9 26

The cutaneous nodules obtained from seven patients with von Recklinghausen's neurofibromatosis were investigated by electron microscopy, and ultrastructural localization of acetylcholinesterase activity was demonstrated in the nerve fibers of this tumor for the first time using Karnovsky's thiocholine method. The enzymatic activity was mainly found in unmyelinated fibers, exactly associated with their axonal membranes, the interspace between the apposing axonal and Schwann cell membrane, and some different mesaxons, which indicated their cholinergic nature. Almost all myelinated fibers and some unmyelinated fibers did not possess the activity. The relationship between axon and Schwann cell was quite similar to that of normal peripheral nervous system, but two striking alterations of the nerves existed: One is the dissociation of unmyelinated fibers, and the other is the degenerative changes of the axon and the myelin sheath. As the evidence of schwannian proliferation, onion bulb formations and collagen pockets were observed. Some signs of fibroblastic proliferation were also found. From the present study and the review of the literature, the probable histogenesis of this disease was discussed.
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PMID:Study on the ultrastructure and acetylcholinesterase activity in von Recklinghausen's neurofibromatosis. 9 62

Serotonin was found to inhibit human erythrocyte and electric-eel acetylcholinesterase activities. The serotonin amino group, free of negative charges in its vicinity and its hydroxyl group, were important for the inhibition. Serotonin precursors and several related compounds had little or no effect. Human plasma cholinesterase was also inhibited by serotonin and tryptamine. In contrast to these animal enzymes, the cholinesterase of Pseudomonas aeruginosa was refractory to serotonin and its derivatives under the same experimental conditions.
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PMID:Comparative study of the sensitivity of acetylcholinesterases and cholinesterases from animal and bacterial sources to inhibition by serotonin and its derivatives. 10 Mar 43

We here report observations on the distribution of acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) in the striatum of the adult human, the rhesus monkey, and the cat. By the histochemical staining methods of Geneser-Jensen and Blackstad and of Karnovsky and Roots, compartments of low cholinesterase activity were identified in parts of the striatum in all three species. In frontal sections, these enzyme-poor zones appeared as a variable number of weakly stained approximately 0.5-mm-wide zones embedded in a darkly stained background. The zones varied in cross-sectional shape from round to elongated and were sometimes branched. They were most prominent in the head of the caudate nucleus. Three-dimensional reconstructions of serial sections through the caudate nucleus in the human and cat suggest that over distances of at least several millimeters, the zones of low enzyme activity form nearly continuous labyrinths.
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PMID:Histochemically distinct compartments in the striatum of human, monkeys, and cat demonstrated by acetylthiocholinesterase staining. 10 1

This investigation was carried out to test the hypothesis that amygdaloid epileptiform activity is due to cholinergic hyperactivity. It was designed to study the underlying physiopathology of, and to act as an experimental model for, psychomotor epilepsy. Neostigmine was injected intracerebrally into the amygdala of the cebus monkey with chronically implanted "chemitrodes" fitted with EEG recording electrodes. The injections were made in the basal amygdaloid nucleus which normally shows very high acetylcholinesterase (AChE) enzymatic activity in histochemical preparations. Neostigmine injection resulted in very high amplitude spike activity in the amygdala only. Other brain areas, including the neighboring temporal cortex, did not show any marked EEG changes. In the first day or two, these EEG changes were associated with myoclonus localized in the ipsilateral muscles of facial expression and also associated with masticatory seizures. Subsequently the animal became aggressive and remained so several months after the injection of neostigmine. The EEG changes continued for approximately 6 weeks. Intramuscular injections of atropine diminished the amplitude of the epileptiform EEG discharges and modified slightly the animal's behavior.
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PMID:Neostigmine activated epileptiform discharge in the amygdala: electrographic-behavioral correlations. 10 9

Biochemical studies were performed on blood and lung tissue of squirrel monkeys (Saimiri sciureus) following acute exposure to 0.75 ppm ozone (O3) for 4 h/d for 4 consecutive days. One group of animals was sacrificed at the end of the last exposure day and another group was sacrificed 4 d later after the last exposure. Evidence was sought for oxidation-induced changes known to occur in rodents when high levels of O3 are inhaled. A significant increase in red blood cell membrane fragility was observed, as well as significant decreases in red blood cell glutathione and erythrocyte acetylcholinesterase; however, the red blood cell enzymes, lactic acid dehydrogenase (LDH), and glucose-6-phosphate dehydrogenase (G6PDH) were not changed significantly. Lung tissue analysis showed that lipid peroxidation was markedly increased and tissue vitamin E levels were significantly decreased. The tissue enzymes G6PDH, glutathione reductase, and LDH significantly increased in activity. No significant changes were seen in either superoxide dismutase or malic acid dehydrogenase. The results of this experiment indicate that O3, or reaction products resulting from O3-tissue interaction in the lung, pass the air-blood barrier and are capable of producing biochemical changes in blood as well as in lung tissue.
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PMID:Biochemical response of squirrel monkeys to ozone. 10 43

1. The effects of diethyl ether (ether) on miniature end-plate currents (m.e.p.c.s) and on acetylcholine-activated end-plate channels were measured in toad sartorius muscle fibres with voltage-clamp and extracellular recording techniques. 2. At low concentrations (less than 20 mM) either made m.e.p.c.s decay faster than normal. At high concentrations (greaster than 40 mM), the decay of m.e.p.c.s was slower than normal. With all concentrations, the cecay remained exponential with single time constant, tau D. 3. At low concentrations ether did not affect the growth phase of m.e.p.c.s and only slightly reduced the amplitude of m.e.p.c.s. At the higher concentrations, the growth phase was slowed and m.e.p.c.s were significantly reduced in amplitude. 4. Ether at all concentrations (5--70 mM) reduced end-plate channel lifetime, the effect increasing with ether concentration. Ether did not significantly alter the elementary channel conductance or the actylcholine null (reversal) potential. 5. Curare reduced tau D which had been prolonged by high concentrations of ether. Ether itself at high concentrations caused a reduction in tau D increased by neostigmine. It is proposed that high concentrations of either inhibit acetylcholine hydrolysis by acetylcholinesterase. 6. The effect of ether in reducing end-plate channel lifetime and reducing m.e.p.c. amplitude, without significantly altering the normal voltage and temperature sensitivity of channel lifetime, is consistent with the proposal that either reduces the stability of open end-plate channels.
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PMID:Dual effects of ether on end-plate currents. 10 8


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