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:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Studies of the synthesis and release of radioactive acetylcholine in rat brain-cortex slices incubated in Locke-bicarbonate-[U-(14)C]glucose media, containing paraoxon as cholinesterase inhibitor, revealed the following phenomena: (a) dependence of K(+)-or protoveratrine-stimulated acetylcholine synthesis and release on the presence of Na(+) and Ca(2+) in the incubation medium, (b) enhanced release of radioactive acetylcholine by substances that promote depolarization at the nerve cell membrane (e.g. high K(+), ouabain, protoveratrine, sodium l-glutamate, high concentration of acetylcholine), (c) failure of acetylcholine synthesis to keep pace with acetylcholine release under certain conditions (e.g. the presence of ouabain or lack of Na(+)). 2. Stimulation by K(+) of radioactive acetylcholine synthesis was directly proportional to the external concentration of Na(+), but some synthesis and release of radioactive acetylcholine occurred in the absence of Na(+) as well as in the absence of Ca(2+). 3. The Na(+) dependence of K(+)-stimulated acetylcholine synthesis was partly due to suppression of choline transport, as addition of small concentrations of choline partly neutralized the effect of Na(+) lack, and partly due to the suppression of the activity of the Na(+) pump. 4. Protoveratrine caused a greatly increased release of radioactive acetylcholine without stimulating total radioactive acetylcholine synthesis. Protoveratrine was ineffective in the absence of Ca(2+) from the incubation medium. It completely blocked K(+) stimulation of acetylcholine synthesis and release. 5. Tetrodotoxin abolished the effects of protoveratrine on acetylcholine release. It had blocking effects (partial or complete) on the action of high K(+), sodium l-glutamate and lack of Ca(2+) on acetylcholine synthesis and release. 6. Unlabelled exogenous acetylcholine did not diminish the content of labelled tissue acetylcholine, derived from labelled glucose, suggesting that no exchange with vesicular acetylcholine took place. In the presence of 4mm-KCl it caused some increase in the release of labelled acetylcholine. 7. The barbiturates (Amytal, pentothal), whilst having no significant effects on labelled acetylcholine synthesis in unstimulated brain except at high concentration (1mm), diminished or abolished (at 0.25 or 0.5mm) the enhanced release of acetylcholine, due to high K(+) or lack of Ca(2+). The fall in tissue content of acetylcholine, due to lack of Ca(2+), was diminished or abolished by pentothal (0.25 or 0.5mm) or Amytal (0.25mm).
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PMID:Control of synthesis and release of radioactive acetylcholine in brain slices from the rat. Effects of neurotropic drugs. 472 96

It is generally believed that neural transmission in the central nervous systems of insects is cholinergic, on the basis of secondary evidence: the presence of cholinesterase, and sensitivity of a nonsynaptic region of the neuron, its cell body, to iontophoresed acetylcholine. In the present work a preparation has been developed which takes advantage of the availability of identified motor neurons in the locust metathoracic ganglion with known 3-dimensional geometry of dendritic fields. These neurons transmit at their peripheral neuromuscular junctions with glutamate. The fast extensor tibiae motor neuron also makes excitatory central connections onto its functional antagonists the flexor tibiae motor neurons. Unless Dale's principle is contravened, transmission at these central synapses should also be glutamatergic. This transmission onto flexor motor neurons was found to be attenuated 70% by a glutamatergic blocker. Glutamate iontophoresed into selected areas of neuropil into which the motor neurons have dendritic branches caused the neurons to be depolarized, in a dose-dependent manner. Individual motor neurons were directly excited to spike with suprathreshold iontophoretic current. With long durations of release they were desensitized, but recovered quickly with rest. The data provide evidence that central transmission onto motor neurons in the locust metathoracic ganglion is glutamatergic.
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PMID:Glutamatergic central nervous transmission in locusts. 609 46

The transfer of detergent solubilized and purified gamma-glutamyl transpeptidase (gamma-GTase), of hog kidney cortex, from proteoliposomes into human erythrocyte ghost membranes has been studied. The transfer of gamma-glutamyl transpeptidase was observed upon incubation of gamma-GTase incorporated dipalmitoylphosphatidylcholine vesicles with erythrocyte ghost membranes at 37 degrees C for 12 h. The extent of transfer was dependent upon the fluidity of donor proteoliposomes, being more when dipalmitoylphosphatidylcholine proteoliposomes were used compared to dimyristoylphosphatidylcholine, and intermediate values were observed when binary mixtures of DMPC and DPPC were used. Moreover, the transfer of gamma-GTase was facilitated when rigid basic phospholipid proteoliposomes were used as donor. The transfer of gamma-GTase has been observed to be associated with the removal of intrinsic membrane proteins and lipids from erythrocytes, mainly acetylcholinesterase, sphingomyelin, and cholesterol. An enhancement in the fluorescence due to resonance energy transfer was observed when ghost membranes containing fluorescent donor probe were incubated with proteoliposomes containing fluorescent acceptor probe, indicating that fusion but not adsorption of vesicles occurs during the transfer process. However, the inability of entrapped [14C]-sucrose delivery from proteoliposomes into ghost membrane vesicle suggest that fusion per se is not primarily involved in the transfer process. It appears that the transfer of gamma-glutamyl transpeptidase occurs by a collisional transfer process resulting in intermembrane protein transfer. The gamma-glutamyl transpeptidase implanted ghost membranes exhibited the uptake of L-glutamate which was inhibited by serine-borate, an inhibitor of transpeptidase activity. In addition, the uptake of L-glutamate was inhibited by the dipeptide gamma-glutamyl-L-glutamate, thus supporting the proposed role of gamma-glutamyl transpeptidase in the uptake of amino acids in biological membranes.
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PMID:Proteoliposome interaction with human erythrocyte membranes. Functional implantation of gamma-glutamyl transpeptidase. 612 71

Brain from 47 avian and 17 mammalian species and the liver from 19 avian and 7 mammalian species has been examined for acetyl cholinesterase and nitrophenyl acetate esterase activities. Plasma from 27 avian and 7 mammalian species has been examined for acetyl cholinesterase, cholinesterase, nitrophenyl acetate esterase, glutamate, oxaloacetate transaminase, glutamate pyruvate transaminase, glutamate dehydrogenase, sorbitol dehydrogenase and lactate dehydrogenase activities. The studies have revealed that variations in enzyme activities occur between species but that there are discernible trends within families. The results indicate that comprehensive control enzyme data is necessary in order to assess the effects of exposure to agricultural chemicals in wildlife.
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PMID:Control enzyme levels in the plasma, brain and liver from wild birds and mammals in Britain. 613 42

The intralaminar distributions of transmitter and nontransmitter enzyme activities and amino acid levels were determined in the midtemporal cortices from normal individuals and established cases of Alzheimer's disease. In the normal, choline acetyltransferase (CAT) and acetylcholinesterase (AChE) activities were relatively high in the outer cortical layers, particularly, for CAT, in the two granular layers (II and IV). Both activities were reduced in Alzheimer's disease at all, although generally most extensively in the outer and middle layers of the grey matter whereas activities were near normal in the white matter. Further, the enzyme distribution patterns of these cholinergic activities were also disrupted in Alzheimer's disease and the activity of CAT throughout the cortex was generally reduced to that found in the white matter. No such differences in distribution were found for two other enzymes, pseudocholinesterase and lactate dehydrogenase. Assessment of the gamma-aminobutyric acid (GABA) system in the normal revealed a much more extensive intralaminar variation in the enzyme, glutamate decarboxylase, compared with the level of GABA itself. In contrast with the cholinergic enzymes, neither the levels nor intralaminar patterns of GABA were altered in Alzheimer's disease. From an analysis of free amino acids at the different cortical levels, the cortical pattern of glutamic acid in the normal was different from that for GABA, aspartic acid, or nontransmitter amino acids such as alanine. Neither of the putative amino acids, glutamate or aspartate, was altered in Alzheimer's disease. These findings demonstrate the relatively selective nature of microchemical changes occurring in the cortex in Alzheimer's disease and suggest that a functional abnormality in cholinergic input to the outer neocortical layers (I-IV) with predominantly receptive and associative functions may be an important feature of the disease.
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PMID:Intralaminar neurochemical distributions in human midtemporal cortex: comparison between Alzheimer's disease and the normal. 614 24

Activities of 12 enzymes (amylase, lipase, cholinesterase, nonspecific carboxyl esterase, lactate dehydrogenase (LDH), alkaline phosphatase, glutamate-oxalacetate transaminase (GOT), glutamate-pyruvate transaminase (GPT), gamma-glutamyl transferase (gamma-GT), leucine aminopeptidase (LAP), malate dehydrogenase (MDH) and peroxidase) were determined in the perienteric fluid and homogenate of Ascaris suum. With the exception of amylase, all activities were higher in the homogenate than in the perienteric fluid. The enzyme activities in the perienteric fluid were then compared with those in the human serum. Comparable activities were demonstrated for LDH, LAP, lipase and alkaline phosphatase, markedly higher activities in perienteric fluid were demonstrated for MDH, GOT, GPT and amylase, and much lower for cholinesterase. No gamma-GT activity was detected in the perienteric fluid.
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PMID:Activities of some enzymes in the perienteric fluid of Ascaris suum. 619 63

In the sheep medulla oblongata, on the induction of polarity by the applied voltage gradient of direct current along the length, the enzymes such as acetylcholinesterase and glutamate dehydrogenase showed anodal transport while the enzyme arginase showed cathodal transport indicating the possession of negative and positive charge densities on the enzymes. These studies indicated that the glutamate bound metabolism, one towards ammonia formation and the other towards the energy production and neural transmission, have opposed electro-characteristics. The acetylcholinesterase system had anodal characteristics coupled to the glutamate dehydrogenase patterns. The existence of two charge based compartmentation is envisaged in the neural tissue.
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PMID:A biphasic compartmentation of neuro-transmission associated metabolic patterns during electro-induced axoplasmic transport in sheep medulla oblongata. 619 98

A previous study identified, by conduction velocity following optic nerve shock, 3 classes of retinal fibers which project to 3 distinct laminae of the goldfish optic tectum. In the present study, the effect of various pharmacological agents on the synaptic efficacy of each of the 3 classes of retinal fibers was assessed by the use of current source-density analysis. All 3 classes of optic fibers appear to be nicotinic cholinergic. Six different nicotinic antagonists were tested. All 6 were effective in decrementing the responses of all 3 classes to a criterion level: alpha-bungarotoxin (10-8 M), alloferin (10-5 M), curare (10-4 M), metocurine (10-4 M), hexamethonium (10-4 M) and gallamine (10-3 M). Atropine, a muscarinic antagonist, had only a slight effect even at 10-3 M. Five nicotinic agonists tested also decremented synaptic responses: nicotine (10-5 M), carbamylcholine (10-4 M), acetylcholine (10-4 M), succinyl choline (10-4 M) and decamethonium (10-3 M), presumably via cellular depolarization and receptor desensitization. Two inhibitors of acetylcholinesterase prolonged the response at 10-4 M and decremented it as well at 10-3 M. Hemicholinium 3, an inhibitor of the high affinity uptake of choline, produced a gradual activity-dependent decrement in the responses. Beta-bungarotoxin, a presynaptically-acting toxin, abolished not only the postsynaptic components but also the presynaptic components at 10-6 M. In all other cases the presynaptic deflections were generally unaffected, and with the exception of the toxins, a return to at least 90% of the control value was achieved. In contrast, GABA (10-3 M) and bicuculine (10-4 M) both produced no discernible effect on the 3 classes of responses, and glutamate (10-3 M) produced only a slight decrement, which probably represents a non-specific effect.
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PMID:Electrophysiologic evidence that retinotectal synaptic transmission in the goldfish is nicotinic cholinergic. 624 64

Immunohistochemical reactions were conducted, using the antibodies against GFA and S-100 proteins on sections of cerebellum from the homozygous (jj) and the heterozygous (Jj) Gunn rats. Hypertrophy of the fibrous astrocytes was observed but hyperplasia of the glial cells was not. Although the molecular layer was very thin, the Bergmann fibre appeared normal. Among the free amino acids in the cerebellum from the jj rat, glutamate concentration decreased to two-thirds of the control level. The protein profile of the cerebellum from the jj rat obtained by SDS-polyacrylamide gel electrophoresis revealed that the amount of P400 protein that is characteristic of Purkinje cells decreased considerably and there were also some changes of the other unidentified proteins. By two-dimensional electrophoresis, it was observed that in the supernatant from the jj rat cerebellum one protein spot diminished and in the particulate fraction from the jj rat one spot was enormously increased. The activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) in the cerebellum from the jj rat did not differ significantly from that of the control; however, activities of choline acetyltransferase and acetylcholinesterase of the jj rat were about twice as high as those of the control. 2-Deoxyglucose incorporation was maximum in the granular layer from both the jj and the Jj rat cerebella. However, the incorporation in the jj cerebellum was not higher than in the Jj control and even lower in some parts of the jj cerebellum than in the control Jj cerebellum.
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PMID:Cerebellar hypoplasia in the Gunn rat with hereditary hyperbilirubinemia: immunohistochemical and neurochemical studies. 625 97

The activity was determined of sorbitol-dehydrogenase (SDH), cholinesterase (CE), leucine-aminopeptidase (LAP), acid phosphatase (AP), and glutamate-dehydrogenase (GDH) in blood plasma of lambs irradiated with 200, 320, and 450 Rad. Results showed that with the mild form of acute radiation sickness (treatment with 200 Rad) the activity of the blood enzymes did not change. With the severe (320 Rad) and the peracute (450 Rad) forms of the disease within the first 24 hours the activity of SDH and CE rose 3 to 5 times, and that of GDH and AP--twice within a period of 1 to 3 days following irradiation. In the case of a threefold increased activity of SDH and CE within 15 to 24 hours of treatment the diseased animals died. Parallel hematologic investigations revealed that well manifested leukopenia with these two forms of the sickness took place after the 24th hour. Activity determination of the investigated plasma enzymes within the first 15-24 hours following irradiation could be used as an adjunct test to the study of the hematologic indices for the early diagnosis of the severe and peracute forms of irradiation sickness as well as for the exit of the disease.
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PMID:[Enzyme activity in the blood plasma of lambs with acute radiation sickness]. 666 25


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