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)

Myelin was purified from adult rabbit sciatic nerve by two procedures: discontinuous gradient centrifugation and continuous gradient zonal centrifugation. Two fractions were obtained from the discontinuous gradient. The fraction floating on 0.32 M sucrose and the fraction recovered from the 0.32/0.85 M sucrose interface showed typical myelin membranes by electron microscopy and typical myelin proteins by gel electrophoresis. The specific activity of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) decreased from the top to the bottom of the discontinuous gradient. The myelin separated by zonal centrifugation on a continuous sucrose gradient showed three distinct peaks (on monitoring optical density) at 0.10, 0.30 and 0.57 M sucrose. The latter peak yielded 92% of the material applied. The two minor peaks of low density exhibited high CNP and acetylcholinesterase (AChE) activities but the specific activity of both enzymes increased markedly at the heavy end of the gradient. The zonal fractions showed typical myelin proteins in all fractions by polyacrylamide gel electrophoresis but with important quantitative differences. These results indicate that PNS myelin shows significant heterogeneity.
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PMID:Distribution of PNS myelin proteins and membrane enzymes in fractions isolated by continuous gradient zonal centrifugation. 22 18

We have found that interleukin 3 (IL-3), a growth factor for hematopoietic cells, is a novel trophic factor for mouse and rat central cholinergic neurons. It enhanced neurite outgrowth and elevated choline acetyltransferase activity. The effect seems to be specific for cholinergic neurons, since somatostatin release and glutamic acid decarboxylase and 2',3'-cyclic nucleotide 3'-phosphodiesterase activities were not significantly influenced by IL-3. In vivo, IL-3 was infused into the lateral ventricles of rats after unilateral axotomy of the septohippocampal pathways. Two weeks later, the IL-3-treated animals showed significant numbers of acetylcholinesterase-positive neurons remaining in the septal region.
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PMID:Interleukin 3 as a trophic factor for central cholinergic neurons in vitro and in vivo. 215 41

The influence of dexamethasone on the development of neurons and oligodendrocytes was studied in serum-free, aggregating rat brain cell cultures. Synaptogenesis and myelination occur in this culture system. The concentration of myelin basic protein and the activity of 2',3'-cyclic nucleotide 3'-phosphodiesterase were used as oligodendroglia and myelin markers. Choline acetyltransferase and acetylcholinesterase served as neuronal markers, glutamine synthetase reflected astrocyte differentiation, while ornithine decarboxylase served as a general marker for cell growth and maturation. This study showed that dexamethasone stimulated the differentiation of cholinergic neurons and astrocytes. The effect of dexamethasone on oligodendroglial differentiation and myelination depended on the stage of development: during the early phase of myelination dexamethasone had a stimulatory effect, whereas at a later stage it showed a significant inhibition.
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PMID:Dexamethasone stimulates the biochemical differentiation of fetal forebrain cells in reaggregating cultures. 242 5

Methylmercury (MeHg) and triethyllead (Et3Pb) are known to cause neurologic impairment in human and in several animal models. In the developing central nervous system the formation of myelin is particularly vulnerable. To obtain more information on the toxic mechanisms related to dysmyelination, the effects of MeHg and Et3Pb on two marker enzymes of myelination was assessed in developing rats. From the 5th day of life intraperitoneal injections of MeHgCl or Et3PbCl at doses of 0.05 to 5 mg/kg body weight were administered to the rats three times a week. They were decapitated at the 21 to 23rd (group A) or at the 28 to 31st postnatal day (group B). The animals treated with 2 mg/kg MeHg or Et3Pb appeared normal and the rate of growth was unchanged compared with that of control rats. A decreased activity of the enzymes UDP galactose:ceramide galactosyltransferase (CGalT) and 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNP) was apparent already at doses of 0.1 mg/kg in group B rats. (MeHg, 18 and 16%, respectively; Et3Pb, 11 and 14%) and the values decreased further with increased toxic doses. In the MeHg-treated animals the exposure time was decisive for the effect; thus in group A of MeHg-treated animals the change in enzyme activities was minimal at doses which in group B had an inhibitor effect. The activities of brain acetylcholinesterase and succinate dehydrogenase were not affected. The results emphasize a common early effect of MeHg and Et3Pb on enzymes associated with myelination in the developing central nervous system.
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PMID:UDPgalactose:ceramide galactosyltransferase and 2',3'-cyclic-nucleotide 3'-phosphodiesterase activities in rat brain after long-term exposure to methylmercury or triethyllead. 298 18

A rat brain P3 fraction enriched in ER derived microsomes was centrifuged through a 20-40% linear sucrose gradient in a Beckman Ti-14 Zonal rotor and 11 fractions were obtained. The distribution of marker enzyme activities and protein were determined in these 11 subfractions. NADPH-Cytochrome C reductase, choline phosphotransferase were employed for endoplasmic reticulum, Na+,K+-ATPase, 5'-nucleotidase, and acetylcholinesterase were employed for plasma membrane, 2',3'-cyclic nucleotide phosphohydrolase was employed for myelin. The bulk of the protein was recovered in the 24-34% sucrose fractions, Na+,K+-ATPase, 5'-nucleotidase, and acetylcholinesterase were in the 22-38% sucrose fractions while NADPH-cytochrome C reductase and CNPase were enriched in the 20-22% sucrose fractions. The ethanolamine and the serine base exchange activities had a bimodal distribution, with highest specific activities in sucrose fractions 32-34% and 20-24%. Choline base exchange activity was nearly undetectable in all the fractions. The specific activities of CDP-choline phosphotransferase, and phospholipid-N-methyltransferase were highest in the 20-22% sucrose fraction. Phospholipid-N-methyltransferase activity was significantly stimulated in the presence of exogenous phospholipid acceptors as phosphatidylethanolamine or phosphatidylmonomethylethanolamine or phosphatidyldimethylethanolamine, however, the greatest response was with phosphatidylmonomethylethanolamine. The rat brain P3 fraction yielded a population of a membrane at the light end of the sucrose gradient which has a buoyant density similar to myelin but seemed to be enriched with NADPH cytochrome C reductase and phospholipid modifying enzymes. This is in contrast to liver microsomes submitted to a similar fractionation.
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PMID:Distribution of selected phospholipid modifying enzymes in rat brain microsomal subfractions prepared by density gradient zonal rotor centrifugation. 298 22

The changes in brain acetylcholinesterase (AChE), acid phosphatase (APase), and 2',3'-cyclic nucleotide-3'-phosphohydrolase (CNP), and plasma butyrylcholinesterase (BuChE) activities were investigated in hens treated with a single, dermal dose (100-1000 mg/kg) of S,S,S-tri-n-butyl phosphorotrithioate (DEF). Three control groups consisted of hens left untreated, given a single, dermal dose of 500 mg/kg tri-o-cresyl phosphate (TOCP, positive control for organophophorous compound-induced delayed neurotoxicity), or 10 mg/kg O,O-diethyl O-4-nitrophenyl phosphorothioate (parathion, negative control). Brain AChE activity, determined 28 days after application, was significantly inhibited in hens given 500-1,000 mg/kg DEF and in TOCP- and parathion-treated hens. In contrast, brain APase and CNP activities were significantly higher in all treatments as compared with those of the untreated hens. Parathion, however, caused the least increase in these enzymatic activities as compared to DEF or TOCP. A single, dermal dose of DEF or TOCP also caused an initial decrease in plasma BuChE activity with maximum depression of enzymatic activity observed 1 to 7 days after administration. This decrease was dose dependent and the enzymatic activity showed partial recovery with time. Hens treated with single, dermal doses of DEF, ranging from 250 to 1000 mg/kg, developed ataxia which progressed to paralysis in some hens. Histopathologic examination revealed axon and myelin degeneration of the spinal cord and peripheral nerves of some hens. The severity and frequency of the neuropathologic lesions were dose dependent. Neurologic dysfunctions and neuropathologic lesions seen in DEF-treated hens were similar to those exhibited in TOCP-treated hens. While parathion produced acute cholinergic effects, it did not cause delayed neurotoxicity. The changes in brain and plasma enzymes are discussed in relation to their role in the pathogenesis of DEF-induced delayed neurotoxicity.
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PMID:Brain acetylcholinesterase, acid phosphatase, and 2',3'-cyclic nucleotide-3'-phosphohydrolase and plasma butyrylcholinesterase activities in hens treated with a single dermal neurotoxic dose of S,S,S-tri-n-butyl phosphorotrithioate. 395 29

Cyclic AMP-stimulated phosphorylation of membrane proteins in central-nervous-system myelin was investigated, with rabbit brain myelin. Subfractionation of a myelin membrane preparation by sucrose-density-gradient centrifugation produced a rapidly sedimenting population of membrane vesicles containing 5'-nucleotidase and acetylcholinesterase, a light membrane fraction containing myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphodiesterase, and an intermediate membrane fraction containing the highest specific activity of 2',3'-cyclic nucleotide 3'-phosphodiesterase and a small proportion of myelin basic protein. Cyclic AMP stimulation of protein phosphorylation was confined to a protein of Mr 49 700, which co-electrophoresed with the upper component of the Wolfgram protein doublet. Cyclic AMP did not affect the phosphorylation of myelin basic protein. Cyclic AMP-stimulated phosphorylation of this protein followed 2',3'-cyclic nucleotide 3'-phosphodiesterase activity on subcellular fractionation and was correspondingly high in the intermediate or 'myelin-like' fraction on sucrose-density-gradient centrifugation.
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PMID:Endogenous cyclic AMP-stimulated phosphorylation of a Wolfgram protein component in rabbit central-nervous-system myelin. 608 36

The light and heavy smooth-surfaced membranes (LSM and HSM), which had densities corresponding to 1.08 M and 1.28 M sucrose, respectively, were isolated from rat brain and some of their biochemical properties were investigated. Both LSM and HSM showed high Na+,K+-ATPase activity and, in particular, in HSM the activity was four times (21.55 mumol/mg protein/h) higher than that of the brain homogenate. High 2',3'-cyclic nucleotide 3'-phosphodiesterase activity (293.4 mumol/mg protein/h) was characteristic of LSM. 5'-Nucleotidase and acetylcholinesterase activities were also higher in LSM than in HSM. SDS-polyacrylamide gel electrophoresis showed that LSM and HSM had many protein component and that low molecular weight proteins such as proteolipid protein and basic protein were almost absent, in contrast with myelin and myelin-like membrane. GM1 ganglioside constituted the major class of total ganglioside in both LSM and HSM. These biochemical findings suggested that LSM is a membrane that has not previously been described, or a membrane fraction related to the oligodendroglial plasma membrane.
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PMID:Further studies on the smooth-surfaced membranes isolated from rat brain. 625 69

The location of 2',3'-cyclic nucleotide 2',3'-phosphodiesterase in human erythrocyte membranes was determined. This was accomplished by comparing the enzyme's accessibility with that of glyceraldehyde-3-phosphate dehydrogenase (cytoplasmic surface marker) and acetylcholinesterase (external marker) in sealed and unsealed ghosts and normal and inverted membrane vesicles. The results showed that 2',3'-cyclic nucleotide 3'-phosphodiesterase, like glyceraldehyde-3-phosphate dehydrogenase, meets several criteria for an inner (cytoplasmic) membrane location: (1) the enzyme was accessible to substrate in unsealed ghosts and inside-out vesicles but not in sealed or right-side-out vesicles, (2) latent activity in sealed ghosts could be exposed with detergent (Triton X-100), (3) activity in unsealed ghosts was gradually sequestered during resealing and could be re-exposed with detergent, and (4) the enzyme was susceptible to trypsin proteolysis only in unsealed ghosts. These results demonstrate that the active site of 2',3'-cyclic nucleotide 3'-phosphodiesterase faces the cytoplasm of erythrocytes and that the enzyme may not span the lipid bilayer of the membrane. The localization of the phosphodiesterase on the inner membrane surface of erythrocytes suggests that the similar enzyme of myelin may be embedded within the major dense line of the compact lamellae.
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PMID:Localization of 2',3'-cyclic nucleotide 3'-phosphodiesterase in human erythrocyte membranes. 627 4

In order to elucidate molecular mechanisms underlying brain dysfunction in offspring exposed to ethanol in utero, subclinical doses of ethanol that do not have apparent structural effect on the offspring were administered intraperitoneally to pregnant rats at various gestational stages. We measured the activity of membrane marker enzymes and the level of mRNA of myelin proteins of the offspring brain. The activity of a myelin specific enzyme, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) decreased in ethanol-exposed offspring. This effect was not related to the period of gestation or the dose of ethanol. Perikaryonal enzymes, acetylcholinesterase and Na+, K(+)-ATPase, were significantly affected in groups exposed to ethanol at early fetal stage and in high doses. Expression of mRNAs of CNP and myelin basic proteins decreased significantly in the ethanol-treated group, with abnormal developmental profile suggesting a relationship with delayed myelination in offspring exposed to ethanol in utero. The present findings suggest that in spite of the low doses of ethanol that do not cause clinical symptoms in the offspring, prenatal exposure to ethanol affects the level of mRNA of membrane enzyme proteins in the offspring brain, consequently causing a corresponding reduction in enzyme activity, that may lead to neuronal dysfunction. In a separate study, blood ethanol levels were found to reach a maximum level within 30 min after injection and be undetectable after 5 to 10 h. No accumulation effects due to daily injection were observed.
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PMID:Prenatal ethanol exposure affects the activity and mRNA expression of neuronal membrane enzymes in rat offspring. 752 23


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