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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)

Subcellular distribution and some extraction properties of acetylcholinesterase (AchE) (EC 3.1.1.7) and nonspecific cholinesterase (ChE) (EC 3.1.1.8) were studied in rat liver employing subcellular fractionation techniques. All purified subcellular fractions were enriched in total cholinesterase activity over the homogenate. Plasma membrane and Golgi fractions showed a significant enrichment in AchE activity, while ChE activity was enriched in both rough and smooth endoplasmic reticulum. Subcellular fractions were subjected to conditions that selectively release proteins having varying degrees of association to membranes. High-pH treatment (known to release peripheral and soluble proteins) extracted ChE activity, but more than 90% of AchE activity remained associated to the pellet. Solubility properties and molecular forms of AchE and ChE in this tissue were studied by extraction in high-salt medium with and without Triton X-100, followed by velocity sedimentation centrifugation. Most of AchE activity (88%) (41% G4 and 59% G2 + G1) was detergent soluble; 42% of ChE activity (detected only as G2 + G1) was high-salt soluble, whereas remaining ChE activity was detergent soluble. These results indicate not only a different subcellular location for both enzymes, but also point to a differential association to membranes. AchE behaves as an integral membrane protein and ChE behaves as a peripheral or a luminal soluble protein.
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PMID:Acetylcholinesterase and nonspecific cholinesterase activities in rat liver: subcellular localization, molecular forms, and some extraction properties. 261 91

Following voluminous injections of horseradish peroxidase (HRP) in various neocortical fields, a small number of labeled large neurons are observed ipsilaterally in the putamen, striatal ponticuli, caudate nucleus, and nucleus accumbens septi. The bulk of the corticopetal cells are found in the putamen and in the striatal ponticuli. A more significant number of labeled neurons is encountered following injections in auditory and sensorimotor cortex, followed by the prefrontal and premotor cortex; very few cells project to the visual cortex. Ultrastructurally, the large HRP-labeled neurons display an eccentrically located, indented nucleus, abundant granular endoplasmic reticulum forming Nissl bodies, well developed Golgi zones, and numerous dense bodies. The simultaneous demonstration of retrogradely transported HRP and acetylcholinesterase (AChE) suggest that the large neurons are presumably cholinergic. These results provide evidence that at least some of the giant striatal neurons are efferent cells. The coincidence of cytological, histochemical, and hodological criteria invite the speculation that the giant corticopetal neostriatal neurons might be related to the magnocellular cholinergic groups of the basal forebrain (especially the Ch4 group).
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PMID:Cortical projection of giant neostriatal neurons in the cat. Light and electron microscopic horseradish peroxidase study. 271 22

In the present study we have determinated the acetylcholinesterase molecular forms present in rat liver hepatocytes; we have also studied the association of acetylcholinesterase with the cell surface of the hepatocytes. Subcellular fractionation indicated that rough endoplasmic reticulum and plasma-membrane-enriched fractions contains G4 and G2 acetylcholinesterase forms bound to membranes. Hepatocytes incubated with phosphatidylinositol-specific phospholipase C released about 70% of the surface acetylcholinesterase. Sedimentation analysis showed that all the solubilized acetylcholinesterase activity comes exclusively from a G2 dimer. The G4 hydrophobic form of acetylcholinesterase accounts for the additional cell-surface activity. The existence of these two forms of acetylcholinesterase on the surface of hepatocytes was further established by analyzing the phosphatidylinositol-specific phospholipase C sensitivity of the acetylcholinesterase molecular forms present in isolated rat liver plasma membranes.
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PMID:Different membrane-bound forms of acetylcholinesterase are present at the cell surface of hepatocytes. 273 51

A daily dose of 3 x 10(6) or 6 x 10(6) units of alpha-interferon was given during two 4- to 6-month periods to a 65-yr-old male patient with hairy cell leukemia, reducing splenomegaly and decreasing the number of hairy cells. Liver biopsy specimens taken during treatment revealed predominantly decreased hairy cell infiltration in the dilated sinusoids and enlarged or vacuolar nuclei of hepatocytes, compared with those in the liver before treatment. The ultrastructure of hepatocytes in specimens taken during treatment showed cytoplasmic vacuoles, weakly stained glycogen particles, and conspicuously decreased endoplasmic reticulum. Liver tests revealed decreased serum cholinesterase and total cholesterol levels in the early stage of treatment, low levels of total protein and albumin during treatment, and a very low value in the [13C]aminopyrine breath test. No clinical reports have been made on the decreased microsomal function during treatment with interferon. alpha-Interferon damaged the endoplasmic reticulum of hepatocytes, although it was effective for the reduction of hairy cells in the liver of hairy cell leukemia.
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PMID:The effect of alpha-interferon on the liver in a patient with hairy cell leukemia: light and electron microscopic studies. 275 86

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

Structural-functional reconstructions of the frog autonomic interneuronal synapsis have been studied at its activation with endogenic acetylcholine under conditions of acetylcholinesterase suppression. The investigation has been performed with preparations of isolated sympathetic trunk of Rana temporaria treated with armine (5 X 10(-6) M) and subjected to electrostimulation (5 imp/sec) up to a complete block of the synaptic transmission. Certain structural changes are revealed in the axo-somatic synapses, demonstrating an increased adhesive properties of the membranes, ("hatch-like" membranes, numerous submembranous aggregates, aggregates of the intercellular cleft and neuronal-glial contacts). In the terminals changed according to the "light type", with poorly manifested changes, light synaptic vesicles loose their spheric form, their diameter decreases. In the boutons with more intensive changes, the vesicles gradually change into the mass of cluster-floccular material. In the boutons with intensively manifested disorders in the ultrastructure, a complete destruction of the light vesicles is observed. The great part of the ganglionic neuron bodies changes according the "dark type". In their neuroplasm a great amount of subsuperficial cisterns of the endoplasmic reticulum and formation of powerful fasciculi of microfilaments are noted to appear.
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PMID:[Ultrastructural changes in the autonomic interneuronal synapse during activation in the presence of acetylcholinesterase suppression]. 301 72

An acetylcholinesterase (AChE) activity and a cholinesterase (ChE) activity were localized in mammalian kidneys, using a modified histochemical method of Koelle. The animals studied were mouse, hamster, cat, rat, and guinea pig. The kidneys were excised after in situ perfusion and fixation to eliminate AChE and ChE activities of blood. We carried out a relatively long incubation (up to 4 h) to detect weak AChE and ChE activities in the tissue. The differences in enzymatic activities in the kidneys from these 5 animals were important. The AChE activity was localized in the glomerulus (mouse, hamster, cat, and rat) and in the tubule (mouse, hamster, and rat). The ChE activity was also localized in the glomerulus (mouse and rat) and in the tubule (mouse and cat). An important nonspecific esterase activity was observed in the tubules of rat, guinea pig, and cat. In the thin segment of the loop of Henle, except of cat kidney, no esterase activity at all was observed. Electron microscopy revealed that, in the mouse kidney, both AChE and ChE activities were localized in the endoplasmic reticulum of glomerular endothelial cells and mesangial cells. (An AChE activity was localized mainly in mesangial cells, while ChE activity was localized mainly in endothelial cells). AChE and ChE activities were also localized in the endoplasmic reticulum of tubule cells.
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PMID:A histochemical localization of acetylcholinesterase and cholinesterase activities in mammalian kidneys. 309 Aug 31

The rat core-specific lectin (CSL) or mannan-binding protein is synthesized and secreted by rat hepatocytes and H-4-II-E hepatoma cells. Prior to secretion proline and lysine residues with collagen-like sequences undergo hydroxylation and subsequent glycosylation of hydroxylysine to produce glucosylgalactosylhydroxylysine. Hydroxylation and subsequent glycosylation are inhibited by alpha,alpha'-dipyridyl (Colley, K. J., and Baenziger, U. U. (1987) J. Biol. Chem. 262, 10290-10295). We have used alpha,alpha'-dipyridyl to investigate the role of hydroxylation and glycosylation on interchain disulfide bond formation, assembly of subunits into high molecular weight complexes, attainment of carbohydrate and lipid binding ability, and secretion. Formation of disulfide-bonded dimers and trimers in the endoplasmic reticulum, assembly into high molecular weight complexes in the Golgi, and attainment of carbohydrate binding activity occur in either the presence or absence of these post-translational modifications. The mature fully processed form of the CSL binds hydrophobic matrices and is secreted at a slow, but linear, rate. Inhibition of proline and lysine hydroxylation and hydroxylysine glycosylation prevents CSL secretion and attainment of binding activity for hydrophobic matrices. Secretion of the lectin, although slow, appears to be an active process and may be related to the capacity to interact with membranes and/or lipids. Other proteins known to contain collagen-like sequences such as acetylcholinesterase, pulmonary surfactant apoproteins, and C1q also interact with lipids and/or membranes. The collagen-like domains of these proteins may also play a role in promoting such interactions.
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PMID:Post-translational modifications of the core-specific lectin. Relationship to assembly, ligand binding, and secretion. 311 40

Acetylcholinesterase activity was found in the cell bodies and extracellularly in the neuropile of the cerebral ganglia of the adult trematode parasite, Fasciola hepatica. Within neuronal cell bodies of the cerebral ganglion, acetylcholinesterase reaction product was found in the endoplasmic reticulum, in the cisternae of the Golgi apparatus, and in secretory vesicles near the inner (releasing face) cisternae. Acetylcholinesterase reaction product was not seen intracellularly within any nerve processes. The reaction product was found around the somatic cell membranes and in the extracellular space between closely apposed nerve processes in the neuropile. Acetylcholinesterase reaction product was associated with synaptic endings that contained clear spheroidal synaptic vesicles, and the reaction product was localized at the site of synaptic contact between the zone of apposition of the pre- and postsynaptic terminals. This intracellular and extracellular distribution of the enzyme is consistent with its function as the degrading enzyme in cholinergic transmission.
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PMID:Histochemical localization of acetylcholinesterase in the cerebral ganglia of Fasciola hepatica, a parasitic flatworm. 319 24

The frequency of pineal ganglia associated with the pineal tract, and the numbers of acetylcholinesterase-positive neurons in these ganglia were studied in the domestic fowl during the post-hatching period by means of the acetylcholinesterase method. Furthermore, the degeneration of nerve cells in pineal ganglia of 40-day-old domestic fowl was investigated in detail at the electron-microscopic level. The rate of pineal organs containing one or more ganglia was 50% in 2- to 13-day-old, 38% in 40-day-old, and only 10% in 1-year-old domestic fowl. In parallel, the number of acetylcholinesterase-reactive nerve cells that constitute individual pineal ganglia decreased after hatching. Various degrees of neuronal degeneration were found in the pineal ganglia: swelling of the endoplasmic reticulum, electron-dense degeneration of the cytoplasm, and pyknosis of the nerve cell nucleus. Clusters of macrophages containing numerous lysosomes filled with debris-like material were scattered in the ganglion. In addition, plasma cells were observed in association with degenerating nerve cells. These results confirm the suggestion that the loss of acetylcholinesterase-positive nerve cells in the pineal ganglia of the domestic fowl is due to naturally occurring, programmed neuronal cell death. This process is discussed with reference to phenomena of cell death observed in other components of central nervous system.
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PMID:Neuronal degeneration in the pineal ganglion during the post-hatching development of the domestic fowl. 319 82


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