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)

In the PC12 clonal nerve cell line derived from a rat pheochromocytoma, the activity of acetylcholinesterase (AChE) is regulated by nerve growth factor (NGF). The specific activity of AChE was significantly increased 2 days after exposure of PC12 cells to NGF (8 X 10(-8) M), and reached its maximal increase of 94% after 3 days. Thereafter the specific activity of AChE did not significantly vary during the following 7 days. AChE cytochemistry showed the enzyme activity to be localized predominantly in cisternae of the rough endoplasmic reticulum, with a strongly enhanced activity after NGF treatment.
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PMID:Regulation of acetylcholinesterase by nerve growth factor in the pheochromocytoma PC12 cell line. 705 5

The addition of nerve growth factor (2.5S NGF) to serum-free aggregating cell cultures of fetal rat telencephalon greatly stimulated the developmental increase in choline acetyltransferase activity. Two other neuronal enzymes, acetylcholinesterase and glutamic acid decarboxylase, showed only slightly increased activities after NGF treatment whereas the total protein content of the cultures and the activity of 2',3'- cyclic nucleotide phosphodiesterase remained unchanged. The stimulation of choline acetyltransferase was dependent on the NGF media concentrations, showing a 50% maximum effect (120% increase) at approximately 3 ng/ml (10-10 M 2.5S NGF). NGF treatments during different culture periods showed that the cholinergic neurons remained responsive for at least 19 days. The continued treatment was the most effective; however, an initial treatment for only 5 days still caused a significant stimulation of choline acetyltransferase on day 19. The observed stimulation appeared to be specific to NGF. Univalent antibody fragments (Fab) against 2.5S NGF completely abolished the NGF-dependent increase in choline acetyltransferase activity, whereas Fab fragments of control IgG were ineffective. Furthermore, angiotensin II, added in high amounts to the cultures, showed no stimulatory effect. The present results suggest that certain populations of rat brain neurons are responsive to nerve growth factor.
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PMID:Nerve growth factor (NGF) stimulation of cholinergic telencephalic neurons in aggregating cell cultures. 705 24

The history of a 6-year-old girl with a tumor originating from thoracic spine and finally becoming resistant to surgery, radio-, and chemotherapy is reported. Tumor-biopsy material was studied by light and electron microscopy, in cell culture, by acetylcholinesterase ultracytochemistry, and by quantitative catecholamine analysis and this led to the rejection of the initial diagnosis of a neuroblastoma. Light microscopy revealed a uniform population of undifferentiated cells incompletely lobulated by broad fibrovascular septa. Using the electron microscope, cells were characterized by large intracellular pools of glycogen, little cytoplasm with an abundance of free ribosomes and a paucity of organelles. A few cells displayed desmosome-like attachment sites. Staining for specific and unspecific acetylcholinesterase was negative with light and electron microscopy, as were the results of catecholamine histofluorescence using the glyoxylic acid method. The latter result was confirmed by the negative outcome of quantitative analyses of dopamine, noradrenaline, and adrenaline with high pressure liquid chromatography nd electrochemical detection in tissue samples. Tumor cells could easily be maintained in culture for up to 4 weeks. None of a variety of treatments that are known to favor expression of neuronal characteristics in neuroblastoma cells (serum withdrawal, nerve growth factor, dbcAMP, dexamethasone) induced morphological differentiation in cultured tumor cells. On the basis of the clinical history, morphology, and of our experiments with tumor cells, the diagnosis of a so-called extraskeletal Ewing's sarcoma is most likely. Our results strengthen the view that a cell biology approach may be valuable in neuroblastoma differential diagnosis.
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PMID:Ultrastructural, biochemical, and cell-culture studies of a presumed extraskeletal Ewing's sarcoma with special reference to differential diagnosis from neuroblastoma. 711 92

Studies are elaborated on regulation of acetylcholinesterase activity by nerve growth factor (NGF) in cultures of clonal PC12 pheochromocytoma cells. Acetylcholinesterase specific activity in these cultures is maximally and half-maximally increased by NGF concentrations of approximately 1-1.5 and 0.5 nM, respectively. These increases are blocked by antiserum to NGF and are neither mimicked nor significantly altered by epidermal growth factor (1-1000 ng/ml), dexamethasone (10 microM), or dibutyryl cAMP (1 mM). The action of NGF on acetylcholinesterase activity is abolished by low concentrations of the inhibitors of RNA synthesis, camptothecin and actinomycin D. Such findings indicate a transcriptional requirement for this effect of NGF. A series of PC12 variants were employed that in serum-containing medium do not show normal PC12 responses to NGF such as cessation of proliferation and neurite outgrowth. Each of the variants exhibited NGF-dependent increases in acetylcholinesterase specific activity. This suggests that the effects of NGF on regulation of acetylcholinesterase activity can be dissociated from the effects of the factor on neurite outgrowth and proliferation, and that NGF may therefore work via parallel or branching pathways.
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PMID:Regulation of acetylcholinesterase activity by nerve growth factor. Role of transcription and dissociation from effects on proliferation and neurite outgrowth. 724 Feb 10

PC12, a clonal line of rat pheochromocytoma, synthesizes, stores, and secretes dopamine and acetylcholine. The cells take up choline by a saturable process and rapidly convert the accumulated choline to acetylcholine. This choline transport has a Km of 12 microM, is Na+ and energy independent, and is relatively insensitive to hemicholinium-3 (IC50 approximately 50 microM). Different ionic conditions can modulate the choline transport. Uptake was increased by pretreatment with 55 mM K+ whereas it was decreased in the presence of 55 mM K+. Choline uptake had similar characteristics in PC12 cells that had been induced to extend neurites by treatment with nerve growth factor. In undifferentiated PC12 cells, storage of newly synthesized acetylcholine was found in bound and free compartments as evidenced from subcellular fractionation. The free pool had a faster turnover rate. Most of the newly synthesized acetylcholine was rapidly degraded in the absence of a cholinesterase inhibitor while continuous incubation with labeled choline resulted in a slow incorporation of newly labeled acetylcholine into a bound pool. The accumulation of acetylcholine in the bound pool, but not acetylcholine synthesis, was inhibited by each of several agents that are known to interfere with the generation or maintenance of proton electrochemical gradients. The newly synthesized acetylcholine could be released from PC12 cells by incubation of the cells with 55 mM K+. These properties indicate that PC12 cells are a good system for studying acetylcholine metabolism by secretory cells.
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PMID:Choline and acetylcholine metabolism in PC12 secretory cells. 728 37

In rat pheochromocytoma (PC12) cells treated with nerve growth factor (NGF), there are several molecular forms of the enzyme acetylcholinesterase (AChE) which sediment on sucrose density gradients at 4 to 6, 10, and 16 S, respectively. We have investigated the cellular localization of these forms in PC12 cells. In order to determine which forms are soluble and which are membrane bound, we extracted PC12 cells in buffers of various ionic strengths and detergent compositions. To distinguish internal from external forms of the enzyme, we examined the effect of di-isopropyl fluorophosphate and BW284c51 dibromide, membrane-permeable and -impermeable inhibitors of AChE, respectively, AChE forms in intact cells. We also determined the susceptibility of the forms in intact cells to collagenase treatment. Based on these studies, we conclude that the globular G1 and G2 (4 to 6 S) forms are internal and consist of both soluble and membrane-associated species. Thirty percent of the G4 (10 S) form is bound to cytoplasmic membrane structures, while the remainder occurs as an integral component of the plasma membrane. The asymmetric A12 (16 S) form is also a surface protein but is extracted by high salt without detergent and is released from intact cells by collagenase. This form thus contains a collagenous domain and is located outside of the plasma membrane, where it may be associated with an extracellular matrix.
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PMID:Cellular localization of the molecular forms of acetylcholinesterase in rat pheochromocytoma PC12 cells treated with nerve growth factor. 731 Apr 86

PC12 cells, a nerve growth factor-responsive clone of rat pheochromocytoma, contain a membrane-bound adenylate cyclase, which can be activated by adenosine analogs. The characteristics of the cyclase response indicate the presence of stimulatory adenosine receptors. Adenosine analogs also produce a marked increase in the ornithine decarboxylase levels of the cells, and the characteristics of this response suggest that it is linked to the adenylate cyclase-stimulatory adenosine receptors. The ornithine decarboxylase response elicited by 5'-N-ethylcarboxamideadenosine (NECA), a potent stimulatory adenosine analog, is synergistic with that produced by nerve growth factor. Differentiation of the cells with nerve growth factor, however, does not substantially alter either the response of cyclase to the adenosine analog or the magnitude of the adenosine-evoked ornithine decarboxylase response. Treatment of the cells with NECA produces an increase in the phosphorylation of a specific non-histone nuclear protein. While causing little or no morphological alteration by itself, NECA is synergistic with nerve growth factor in producing neurite outgrowth in PC12 cells. NECA does not cause an induction of acetylcholinesterase in the cells. NECA does not cause an induction of acetylcholinesterase in the cells, nor does it appear to affect the induction of this enzyme by nerve growth factor.
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PMID:The action of adenosine analogs on PC12 cells. 733 72

Exposure of naive PC12 cells, sympathetic neurons from rat superior cervical ganglia, and brain-derived septal neurons to epidermal and nerve growth factors simultaneously resulted in some alteration of cellular events induced by nerve growth factor alone. A more pronounced decline of catecholamine content, no additional change in acetylcholinesterase activity, and additive stimulation of RNA and protein syntheses were found in PC12 cells. Earlier elevation of the enzyme activity was observed in sympathetic but not in septal neurons. Epidermal growth factor appeared to support independently the same level of acetylcholinesterase activity in septal neurons as revealed for nerve growth factor during the first week and cell survival throughout 2 weeks of observation. The data obtained indicate that epidermal growth factor augments temporarily some effects of nerve growth factor, thus supporting the idea of an important role of mitogenic growth factors in neural development as complementary and/or substitutive regulators of nerve cell differentiation and survival.
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PMID:Epidermal growth factor influences the neurotrophic/differentiating action of nerve growth factor. 748 19

Nerve growth factor is required for the survival and maintenance of cholinergic neurons in the central nervous system. The direct infusion into the rat's septum of an anti-nerve growth factor monoclonal antibody, which inhibits nerve growth factor bioactivity seven times more strongly than a polyclonal antibody, caused very severe damage to the hippocampal cholinergic system. Anti-nerve growth factor polyclonal antibody also neutralized endogenously occurring nerve growth factor. The infusion of anti-nerve growth factor polyclonal antibody produced a dysfunction of memory and decreased choline acetyltransferase activity and acetylcholinesterase staining in the hippocampus. The cholinergic dysfunction and impairment of memory recovered to the normal level two weeks after cessation of the infusion of the anti-nerve growth factor polyclonal antibody. These results suggest that a deficit of nerve growth factor in the adult brain causes neuronal dysfunction.
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PMID:Memory impairment and neural dysfunction after continuous infusion of anti-nerve growth factor antibody into the septum in adult rats. 750 74

Two experiments were conducted to assess the durability of nerve growth factor (NGF) effects on cholinergic neurochemical markers. Artificial CSF or NGF was infused via osmotic pumps for 2 weeks into the lateral ventricles of young adult (3- to 6-month-old) and aged (22- to 26-month-old) Fischer 344 rats. Assessment of choline acetyltransferase (CAT) and acetylcholinesterase (AChE) within the cortex, striatum, and hippocampus was conducted either approximately 3 (experiment 1) or 12 (experiment 2) weeks after termination of treatment. A variety of age-related deficiencies were found in the two experiments with decreased marker levels within the dorsal hippocampus and striatum being most consistent. NGF increased cholinergic marker enzyme activity in experiment 1 only. Specifically, NGF (a) attenuated age-related CAT and AChE deficits within the dorsal hippocampus and striatum, (b) enhanced CAT activity within the frontal cortex and ventral hippocampus in aged animals, and (c) increased CAT activity within the dorsal hippocampus in young subjects. It is concluded that NGF may be beneficial in enhancing cholinergic neurochemical parameters, especially in aged animals, but such effects are most likely transient.
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PMID:Transient enhancement of cholinergic neurochemical markers induced by NGF in aged F344 rats. 755 May 95


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