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)

The transsynaptic induction of the monoamine transporter present on the membrane of chromaffin granules was studied in primary cultures of dissociated bovine adrenomedullary cells submitted to a chronic secretory stimulation. The amount of the vesicular monoamine transporter was assayed by binding of the specific ligand [3H]-dihydrotetrabenazine. After several days of incubation in the presence of high potassium, the concentration of [3H]-dihydrotetrabenazine binding sites was increased by a 1.5-2.5 factor. This increase was smaller in the presence of the cholinergic agonist carbachol. The long-term inductions of the vesicular monoamine transporter, of tyrosine hydroxylase, and of acetylcholinesterase were of similar magnitude. Under the same conditions, we found no variation in either the activities of other catecholamine biosynthetic enzymes (dopamine beta-hydroxylase and DOPA decarboxylase), or in metabolic enzymes such as lactate dehydrogenase and cytochrome c oxidase, and a decrease in the cellular content of chromogranin A and cytochrome b-561. The induction of the vesicular monoamine transporter was inhibited by the calcium channel antagonists, fluspirilene and nifedipine, and was increased by the agonist Bay K 8644. It was abolished by cycloheximide and actinomycin D. These results indicate that calcium entry into chromaffin cells increases the synthesis of the vesicular monoamine transporter, presumably by transcriptional activation. Elevation of intracellular cyclic AMP concentration or activation of protein kinase C also induced an increase in the expression of the vesicular monoamine transporter. Our results confirm that components of storage vesicle membranes are differentially regulated in response to secretory stimulation, as are several cytosolic or intravesicular soluble proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of the chromaffin granule catecholamine transporter in cultured bovine adrenal medullary cells: stimulus-biosynthesis coupling. 127 22

This study was designed to elucidate harmful effects of acetylcholine on myocardial mitochondrial electron transport activity. Rats were cervically dislocated 3 h and 6 h after oral administration of pyridostigmine, an acetylcholinesterase inhibitor. The myocardial mitochondrial electron-transport activity (NADH-cytochrome c reductase, succinate-cytochrome c reductase and cytochrome c oxidase), and myocardial acetylcholine and norepinephrine concentrations were measured. Activities of cytochrome c oxidase were significantly decreased in the pyridostigmine-3h and the pyridostigmine-6h groups compared with untreated rats. Activity of NADH-cytochrome c reductase was significantly decreased 6 h after administration. No significant changes were observed in those of succinate-cytochrome c reductase among all groups. Pyridostigmine increased significantly myocardial acetylcholine concentration, however, no significant changes of myocardial norepinephrine concentrations were observed among all groups. It is indicated that these mitochondrial injuries might be dependent on an increase in acetylcholine level and independent of norepinephrine.
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PMID:Changes in myocardial mitochondrial electron transport activity in rats administered with acetylcholinesterase inhibitor. 255 31

Although acetylcholine is known to be involved in the genesis of skeletal muscle disturbance, its effect on cardiac muscle has been scarcely studied. In the present paper, using pyridostigmine, a cholinesterase inhibitor, the possible role of acetylcholine in the genesis of cardiomyopathy was investigated. In a mortality study, it was shown that pyridostigmine (100 mg/kg) caused death of 9/10 rats within 8 h, and that the lethality of such a dose could be significantly diminished by the subsequent administration of a total dose of 4 mg/kg atropine. In all other experiments, rats were divided into three groups; the control, untreated group; the pyridostigmine + atropine group in which atropine (2 mg/kg) was administered 5 min after pyridostigmine (60 mg/kg) administration; and the pyridostigmine group in which pyridostigmine (60 mg/kg) was administered orally. Rats were killed 3 h after pyridostigmine administration, and hearts were isolated. Heart mitochondrial electron transport activity (NADH-cytochrome c reductase, succinate-cytochrome c reductase, and cytochrome c oxidase) were measured enzymatically, and mitochondrial respiratory rates and control indices were measured polarographically. Structural changes in cardiac muscles of each group were observed by electron microscopy of cardiac sections. Acetylcholine levels of left ventricle were measured by high performance liquid chromatography. Activities of NADH-cytochrome c reductase and succinate-cytochrome c reductase were not affected by pyridostigmine administration; however, cytochrome c oxidase activity was significantly reduced in the pyridostigmine group. Atropine markedly lessened this reduction in activity. A protective effect of atropine was also observed morphologically. A protective effect of atropine was also observed morphologically. In the pyridostigmine group and the pyridostigmine + atropine group, left ventricular acetylcholine levels were increased significantly compared with the control.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of acetylcholine in pyridostigmine-induced myocardial injury: possible involvement of parasympathetic nervous system in the genesis of cardiomyopathy. 273 Mar 38

Two main groups of quantitative methods are used in the brain to relate enzymatic processes to cellular structures, i.e. the methods of microchemistry and microscopic histochemistry. Microchemistry tries to quantify enzyme activities in very small brain regions by miniaturizing biochemical methods, whereas microscopic histochemistry applies staining procedures to tissue sections, preserving the structural relationship that is present in situ and giving topological information on the distribution of enzymes which is indispensable in structural heterogeneous tissue as is the brain. The present review deals preferentially with microscopic methods and, in particular, with scanning microphotometry (image plane scanning). Using this technique two measuring procedures can be applied for the quantification of enzyme activities, i.e. end-point and kinetic (continuous monitoring) measurements which are described in detail. Methods for the microphotometric demonstration of certain important dehydrogenases (isocitrate dehydrogenases, succinate dehydrogenase, NAD-linked malate dehydrogenase, glutamate dehydrogenase and glycerol 3-phosphate dehydrogenase), of cytochrome c oxidase, hexokinase and acetylcholinesterase are presented. These methods were adapted for giving optimal demonstration of enzyme activities in the rat hippocampus. The examples are given to illustrate the aptitude and possibilities of this technique in the quantification of enzymes in the complex matrix of the brain.
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PMID:Quantitative enzyme histochemistry in the brain. 306 15

Axolemma-enriched fractions were isolated from the white matter of bovine corpus callosum via a purified preparation of myelinated axons which were osmotically shocked and fractionated on a discontinuous density gradient. Two membrane fractions of differing density were obtained: both were somewhat enriched over white matter whole homogenate in specific activity of acetylcholinesterase and 5'-nucleotidase and maximal binding capacity for saxitoxin. Both membrane fractions contained appreciable amounts of 2', 3'-cyclic nucleotide 3'-phosphohydrolase; the specific activity of antimycin-sensitive NAPH-cytochrome c reductase and cytochrome c oxidase indicated low levels of contamination by microsomal and mitochondrial membrane. The myelin which is concomitantly isolated with the axolemma-enriched fractions has a lipid and protein composition comparable to that of myelin isolated by other procedures. Both axolemma-enriched fractions contain about one half of their dry weight as lipid comprised of approximately 25% cholesterol, 25% galactolipid (cerebrosides and sulfatides in a molar ratio of about 4:1) and 50% phospholipid, mostly choline phosphatides and ethanolamine phospholes in an equimolar ratio. The axolemma fractions are also enriched in ganglioside content relative to the myelin fraction. The polypeptides of the axolemma-enriched fractions range from 20,000 to over 200,000 in molecular weight; the predominant proteins are in the range from 50,000 to 69,000. The most dense axolemma-enriched fraction is over fourfold enriched in glycoprotein content compared with myelin, with at least 10 different molecular-weight classes of glycoproteins as identified by Schiff stain of polyacrylamide gel protein profiles. The differences and similarities in the molecular composition of axolemma-enriched preparations which have been characterized to date are discussed.
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PMID:Composition of axolemma-enriched fractions isolated from bovine CNS myelinated axons. 727 11

The acute effects of ethanol on the nervous system are thought to be associated with disturbance of neural membrane function. In the present study the effects of ethanol, its immediate metabolite, acetyldehyde, and tertiary butanol which is not further metabolized to an aldehyde, on selected membrane-bound enzymes were examined in vitro in rat brain. The enzymes included acetylcholinesterase, succinate dehydrogenase, Na+K+-ATPase and cytochrome c oxidase. At concentrations ranging from 0.07 - 2% w/v (15 - 435 mM) ethanol did not produce significant inhibition of any of the enzymes tested. On the other hand acetaldehyde at concentrations ranging from 0.01 - 0.5% w/v (2 - 114 mM) showed marked inhibition of all the abovementioned enzymes except acetylcholinesterase. The responses of the various enzymes to tertiary butanol were intermediate between those obtained with ethanol and acetaldehyde. Further studies are in progress to evaluate the significance of these findings to the understanding of alcohol intoxication, tolerance and dependence in man.
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PMID:Effect of ethanol and acetaldehyde on membrane-bound enzymes in rat brain. 742 41

We previously demonstrated that feeding rats the Steenbock and Black rickets-inducing diet produces remarkable changes in the metabolic pattern of intestinal mucosa, kidney, liver, cerebral cortex and heart. We have now determined the levels of calcium, phosphorus and citrate in cerebral cortex and the activity of some enzymes in synaptosomes and cerebral cortex mitochondria of three rat groups: control (Group A), fed a vitamin D-deficient diet (Group B), fed a vitamin D-deficient diet and treated with 1,25-dihydroxyvitamin D3 (Group C). While calcium content increased in Groups B and C, phosphorus concentration increased only in Group C and citrate in Group B in comparison with control. The increase in acetylcholinesterase and citrate synthase registered in Group B was restored to control values by 1,25-dihydroxyvitamin D3 treatment, while, neither the decrease in cytochrome c oxidase, nor the increase in glucose-6-phosphate dehydrogenase, acid phosphatase and NADP+(-)isocitrate dehydrogenase observed in Group B were corrected by 1,25-dihydroxyvitamin D3 supply. Acyl phosphatase showed a remarkable increase in consequence of 1,25-dihydroxyvitamin D3 administration.
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PMID:Vitamin D--related modification of enzyme activities in synaptosomes and mitochondria isolated from rat cerebral cortex. 862 85

Acute, severe injury of the rabbit spinal cord, induced by the weight-drop method, causes alterations of the enzyme activities related to cholinergic and energy metabolism. Morphological examinations at the trauma site show degenerative processes in neurons 0.5 hr posttrauma and a marked decrease in the number of living cells 24 hrs later. Both biochemical and cytochemical findings show that the tissue metabolic and morphologic derangement, caused by severe spinal cord injury, is mostly confined to the gray matter at an early stage (0.5 hr), whereas 24 hrs later the white matter is also involved. The decrease in choline acetyl-transferase and acetylcholinesterase activities in the gray matter parallels the impairment of complex IV (cytochrome c oxidase) of the respiratory chain and the presence of morphological alteration in neurons. The dramatic drop in the enzyme activities, observed 24 hrs after the induction of the severe trauma is clearly associated with the loss of cells.
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PMID:Alteration of complex IV and acetylcholine-related enzymes in experimental spinal cord injury. 916 29

We investigated possible changes in bioenergetics at the rostral ventrolateral medulla (RVLM), a medullary site where sympathetic vasomotor tone originates and where the organophosphate poison mevinphos (Mev) acts to elicit cardiovascular intoxication. In Sprague-Dawley rats maintained under propofol anesthesia, microinjection bilaterally of Mev (10 nmol) into the RVLM induced progressive hypotension that was accompanied by an early augmentation (80-100 min post-Mev; Phase I), followed by a decrease (>100 min post-Mev; Phase II) in the power density of the vasomotor components (0-0.8 Hz) in systemic arterial pressure (SAP) signals. Enzyme assay revealed that local application of Mev into the RVLM also significantly and progressively depressed the activity of NADH cytochrome c reductase (marker for Complexes I and III) and cytochrome c oxidase (marker for Complex IV) in the mitochondrial respiratory chain of the RVLM, but not the heart. On the other hand, the activity of succinate cytochrome c reductase (marker for Complexes II and III) remained unaltered. Both the cardiovascular consequences and depression of mitochondrial respiratory chain enzymes elicited by Mev were significantly antagonized on comicroinjection of atropine (3.5 or 7 nmol) bilaterally into the RVLM. We conclude that Mev adversely effects cardiovascular control by acting as a cholinesterase inhibitor in the RVLM, whose neuronal activity is intimately related to the death process. The resulting accumulation of acetylcholine and prolonged activation of muscarinic receptors in the RVLM is manifested by a selective dysfunction of respiratory enzyme Complexes I and IV in the mitochondrial respiratory chain that underlies cardiovascular toxicity associated with organophosphate poisons such as Mev.
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PMID:Depression of mitochondrial respiratory enzyme activity in rostral ventrolateral medulla during acute mevinphos intoxication in the rat. 1517 37

Large-conductance voltage- and calcium-sensitive channels are known to be expressed in the plasmalemma of central neurons; however, recent data suggest that large-conductance voltage- and calcium-sensitive channels may also be present in mitochondrial membranes. To determine the subcellular localization and distribution of large-conductance voltage- and calcium-sensitive channels, rat brain fractions obtained by Ficoll-sucrose density gradient centrifugation were examined by Western blotting, immunocytochemistry and immuno-gold electron microscopy. Immunoblotting studies demonstrated the presence of a consistent signal for the alpha subunit of the large-conductance voltage- and calcium-sensitive channel in the mitochondrial fraction. Double-labeling immunofluorescence also demonstrated that large-conductance voltage- and calcium-sensitive channels are present in mitochondria and co-localize with mitochondrial-specific proteins such as the translocase of the inner membrane 23, adenine nucleotide translocator, cytochrome c oxidase or complex IV-subunit 1 and the inner mitochondrial membrane protein but do not co-localize with calnexin, an endoplasmic reticulum marker. Western blotting of discrete subcellular fractions demonstrated that cytochrome c oxidase or complex IV-subunit 1 was only expressed in the mitochondrial fraction whereas actin, acetylcholinesterase, cadherins, calnexin, 58 kDa Golgi protein, lactate dehydrogenase and microtubule-associated protein 1 were not, demonstrating the purity of the mitochondrial fraction. Electron microscopic examination of the mitochondrial pellet demonstrated gold particle labeling within mitochondria, indicative of the presence of large-conductance voltage- and calcium-sensitive channels in the inner mitochondrial membrane. These studies provide concrete morphological evidence for the existence of large-conductance voltage- and calcium-sensitive channels in mitochondria: our findings corroborate the recent electrophysiological evidence of mitochondrial large-conductance voltage- and calcium-sensitive channels in glioma and cardiac cells.
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PMID:The calcium-sensitive large-conductance potassium channel (BK/MAXI K) is present in the inner mitochondrial membrane of rat brain. 1656 53


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