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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of the neurotoxin aluminum on markers of synaptic neurotransmission, adenosine 3',5'-monophosphate, and neurofilaments have been evaluated in a neuroblastoma x glioma hybridoma (NG108-15). Cells were exposed for 4 days to 2 mM aluminum lactate, a concentration that did not suppress growth. Compared to controls, the activity of choline acetyltransferase was significantly increased by 37% associated with an up-regulation in enzyme activity (Vmax). Muscarinic receptors, measured by [3H]QNB binding, were reduced by 41%. In contrast, the activities of acetylcholinesterase and glutamate decarboxylase were not significantly changed. Aluminum raised the level of cyclic AMP by 20%, although adenylate cyclase activity was unchanged. Small amounts of both phosphorylated and non-phosphorylated neurofilaments were detected in NG108-15 cells. Aluminum intoxication, however, did not alter the quantity, ultrastructure, or immunoreactivity of neurofilaments. Our results demonstrate the capability of aluminum to produce selected changes in cholinergic markers and levels of cyclic AMP in a rapidly dividing cell line.
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PMID:The effect of aluminum on markers for synaptic neurotransmission, cyclic AMP, and neurofilaments in a neuroblastoma x glioma hybridoma (NG108-15). 217 66

The neuroblastoma, N1E-115, was grown for 9 days after subcultivation. The development of acetylcholinestrase (AChE), choline acetyltransferase (CAT), QNB-binding, choline uptake, and acetylcholine release was measured on days 1, 3, 6, and 9. In parallel experiments the irreversible AChE inhibitor soman was added to neuroblastoma on day 1 and the development of the above parameters except for release, was followed. AChE activity in the normal cells was found to develop also after confluency, whereas CAT activity and QNB-binding followed the development of most of the cellular proteins, i.e., ceased to develop at confluency. Both choline uptake and acetylcholine release appeared independent of cellular development. In the soman-treated cells the development of AChE was inhibited for up to 6 days and thereafter developed with the same rate as in the normal cells. CAT and QNB-binding developed as in the normal cells, but at a significantly reduced level. The development of choline uptake was not significantly different in soman-treated and normal neuroblastoma. It is concluded that the development of the cholinergic marker QNB-binding is intimately associated with that of the "presynaptic" marker CAT, whereas the development of AChE seems to be unrelated to these cholinergic parameters. The choline transport and the acetylcholine release seem to be equally well expressed on all the days studied.
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PMID:Development of cholinergic markers in the neuroblastoma, N1E-115. 225 60

Studies have established that major increases in muscarinic acetylcholine receptor (mAchR) binding in the brain appear to coincide with synaptogenesis. The neuroblastoma x glioma hybrid NG108-15 cell line has been demonstrated to possess numerous functional characteristics of intact neurons, including synapse formation with myotubes. The present study examines and characterizes the mAchR on the hybrid NG108-15 cells during differentiation, induced by 1 mM dBcAMP. Specific binding of [3H]-QNB for differentiated cells increases gradually to a final level of 130% (P less than 0.05) over the control undifferentiated cells during the first 24 hr of incubation. Further, this increase of receptor sites appears to correlate proportionately to the degree of neurite extension of the differentiating cells. The dissociation rate constant at equilibrium (Kd) and maximum binding capacity (Bmax) have been determined to be 5.6 nM and 920 fmol/10(6) cells, respectively, for differentiated cells, and 4.4 nM and 400 fmol/10(6) cells, respectively, for undifferentiated cells. Computer analyses of the data obtained from saturation experiments reveal a single class of binding sites for [3H]-QNB on both differentiated and undifferentiated cells. The Hill plot analysis of the QNB-binding indicates a Hill coefficient (nH) of 1.0 and 0.91 for differentiated and undifferentiated cells, respectively, suggesting the unity of receptor sites with no co-operativity. Our results depict that increases of mAchRs on intact cells correlate with the degree of cellular differentiation.
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PMID:Characterization of muscarinic acetylcholine receptors on intact neuroblastoma x glioma NG108-15 cell upon induced differentiation. 254 90

The mechanisms of carbachol-induced muscarinic acetylcholine receptor (mAChR) down-regulation, and recovery following carbachol withdrawal, were studied in the neuroblastoma x glioma hybrid NG108-15 cell line by specific ligand binding assays. N-[3H]Methylscopolamine ([3H]NMS) and [3H]quinuclidinyl benzilate ([3H]QNB) were used as the ligands for the cell surface and total cellular mAChRs, respectively. Exposure of cells to 1 mM carbachol for 16 h decreased the specific binding of [3H]NMS and [3H]QNB by approximately 80%. Bacitracin (1-4 mg/ml) and methylamine (1-15 mM), inhibitors of transglutaminase and of endocytosis, prevented agonist-induced loss of surface mAChRs. Pretreatment of cells with the antimicrotubular agents nocodazole (0.1-10 microM) and colchicine (1-10 microM) prevented carbachol-induced loss of [3H]QNB binding, but not that of [3H]NMS binding. These results indicate that agonist-induced mAChR down-regulation occurs by endocytosis, followed by microtubular transport of receptors to their intracellular degradation sites. When carbachol was withdrawn from the culture medium following treatment of cells for 16 h, receptors recovered and were incorporated to the surface membrane. This recovery process was antagonized by monovalent ionophores monensin (0.1 microM) and nigericin (40 nM), which interfere with Golgi complex function. Receptor recovery was also prevented by the antimicrotubular agent nocodazole. Thus, recovery of receptors appears to be mediated via Golgi complex and microtubular transport to the surface membrane.
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PMID:Mechanism of agonist-induced down-regulation and subsequent recovery of muscarinic acetylcholine receptors in a clonal neuroblastoma x glioma hybrid cell line. 256 88

1. The possibility that a long-lasting neuronal activation regulates the expression of muscarinic cholinergic receptors was studied with three cultured neuronal cell lines. 2. Continuous depolarization of a subclone of the neuroblastoma-glioma NG108-15 hybrid cells with potassium chloride increased by 45-75% the number of cholinergic muscarinic receptors, monitored with 3H-QNB, whereas a short incubation with KCl for 10 min or 6 hr had no effect. 3. The calcium channel blocker verapamil increased the effect of KCl. 4. Two cell lines, named SC9 and WC5, that originate from the rat brain, also bind 3H-QNB. They were therefore used to test whether the effect of chronic depolarization is universal. Depolarized SC9 and WC5 cells, in the presence or absence of verapamil, did not show an increased 3H-QNB binding. 5. Muscarinic receptors of both SC9 and WC5 cells have a higher affinity to pirenzepine than the M-3 receptor subtype of the neuroblastoma-glioma cells, suggesting therefore that the two rat brain cell lines possess M-1 or M-2 receptors. 6. The physiological significance of this differential role of depolarization on the expression of different muscarinic receptors is discussed in the context of their postreceptor second messengers.
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PMID:Neuronal membrane depolarization and the control of cholinergic muscarinic receptors: selective effect on different neuronal cell types. 271 80

Human neuroblastoma cells (clone SHSY-5Y) induced to differentiate by 12-O-tetradecanoylphorbol-13-acetate (TPA) are shown to possess properties characteristic of mature ganglion cells. Elevation of the external K+ concentration, exposure to Ca2+ ionophore A23187, and acetylcholine all stimulate the release of preloaded 3H-noradrenaline in the presence but not in the absence of added Ca2+. Acetylcholine causes a fall in the 86Rb+ or 14C-TPMP equilibrium potential across the plasma membrane and stimulates 86Rb+ efflux. These responses are prevented by atropine. Acetylcholine and muscarine but not nicotine stimulate an increase in 45Ca2+ influx, an effect blocked by atropine. None of these responses have been observed in nondifferentiating cells. Muscarinic receptors, however, as measured by the binding of tritiated quinuclidinyl benzilate (3H-QNB), were present to a similar extent in control and differentiated cells. Both cell types also exhibit an accelerated release of Ca2+ in response to acetylcholine, but the control cells were at least 1 order of magnitude more sensitive to the agonist.
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PMID:Development of a neural phenotype in differentiating ganglion cell-derived human neuroblastoma cells. 309 56

Four nerve agents and one therapeutic organophosphate (OP) anticholinesterase (anti-ChE) bind to acetylcholine (ACh) receptors, inhibit or modulate binding of radioactive ligands to these receptors, and modify events regulated by them. The affinity of nicotinic (n) ACh receptors of Torpedo electric organs and most muscarinic (m) ACh receptors of rat brain and N1E-115 neuroblastoma cultures for the OP compounds was usually two to three orders of magnitude lower than concentrations required to inhibit 50% (IC-50) of ACh-esterase activity. However, a small population of m-ACh receptors had an affinity as high as that of ACh-esterase for the OP compound. This population is identified by its high-affinity [3H]-cis-methyldioxolane ([3H]-CD) binding. Although sarin, soman, and tabun had no effect, (O-ethyl S[2-(diisopropylamino)ethyl)] methyl phosphonothionate (VX) and echothiophate inhibited competitively the binding of [3H]-quinuclidinyl benzilate ([3H]-QNB) and [3H]-pirenzepine ([3H]-PZ) to m-ACh receptors. However, VX was more potent than echothiophate in inhibiting this binding and 50-fold more potent in inhibiting carbamylcholine (carb)-stimulated [3H]-cGMP synthesis in N1E-115 neuroblastoma cells--both acting as m receptor antagonist. All five OPs inhibited [3H]-CD binding, with IC-50s of 3, 10, 40, 100, and 800 nM for VX, soman, sarin, echothiophate, and tabun, respectively. The OP anticholinesterases also bound to allosteric sites on the n-ACh receptor (identified by inhibition of [3H]-phencyclidine binding), but some bound as well to the receptor's recognition site (identified by inhibition of [125I]-alpha-bungarotoxin binding). Soman and echothiophate in micromolar concentrations acted as partial agonists of the n-ACh receptor and induced receptor desensitization. On the other hand, VX acted as an open channel blocker of the activated receptor and also enhanced receptor desensitization. It is suggested that the toxicity of OP anticholinesterases may include their action on n-ACh as well as m-ACh receptors if their concentrations in circulation rise above micromolar levels. At nanomolar concentrations their toxicity is due mainly to their inhibition of ACh-esterase. However, at these low concentrations, many OP anticholinesterases (eg, VX and soman) may affect a small population of m-ACh receptors, which have a high affinity for CD. Such effects on m-ACh receptors may play an important role in the toxicity of certain OP compounds.
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PMID:Direct actions of organophosphate anticholinesterases on nicotinic and muscarinic acetylcholine receptors. 323 34

By Scatchard plot analysis of [3H]QNB (quinuclidinyl benzilate) binding, there are 2 x 10(5) muscarinic sites/cell with a KD about 10 nM in N4TG1 neuroblastoma cells. We have now examined a group of compounds structurally related to aprophen and QNB for their ability to compete with the binding of QNB to the muscarini receptor. Using this structure-inhibition relationship, the functional groups of the muscarinic ligand necessary for binding were partially characterized. It was found that the quinuclidinyl ring structure of QNB can be substituted by either alkane, H, or pyrrolidine at the N without loosing their ability to bind. The addition to the quinuclidinyl ring increases the bulk of the structure and decreases binding. Like the benzilate in QNB, a similar hydrophobic structure is apparently required for the binding.
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PMID:Structure-binding relationship of quinuclidinyl benzilate analogs on N4TG1 neuroblastoma muscarinic receptors. 340 71

The specific binding of the muscarinic ligand [3H](-)quinuclidinyl benzilate [( 3H]QNB) to cell membranes of human SH-SY5Y neuroblastoma cells was studied. Saturation isotherms yielded a Kd = 0.28 +/- 0.06 nM and a Bmax of 337 +/- 47 pmol/g protein. Pirenzepine inhibited [3H]QNB binding; inhibition data showed best fit to a 2-site binding model revealing both a high affinity pirenzepine site (34%, KH = 10 nM) and a low affinity site (66%, KL = 1 microM). These results indicate that muscarinic receptors on SH-SY5Y cells may be subclassified as M1/M2 subtypes. Morphological and biochemical differentiation of these cells after treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or retinoic acid (RA) resulted in a decrease and an increase in the number of muscarinic binding sites, respectively. Furthermore, TPA- and RA-treated cells showed a significant increase in acetylcholinesterase activity compared with non-treated cells. However, only RA-treated cells showed significant increase in choline acetyltransferase activity compared to non-treated cells. These findings demonstrate that TPA and RA can regulate both the number of muscarinic receptors and the acetylcholinesterase activity in human SH-SY5Y neuroblastoma cells.
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PMID:Muscarinic receptors in human SH-SY5Y neuroblastoma cell line: regulation by phorbol ester and retinoic acid-induced differentiation. 360 14

A human neuroblastoma cell line, IMR32, has been characterized as far as morphology, membrane receptors for neurotransmitters, and uptake and release of [3H]3,4-dihydroxyphenylethylamine ([3H]dopamine). These cells expressed at their surface both nicotinic and muscarinic cholinergic receptors, revealed by [125I]alpha-bungarotoxin and [3H]quinuclidinylbenzilate ([3H]QNB) binding, respectively. [125I]alpha-Bungarotoxin binding was efficiently inhibited by alpha-bungarotoxin, nicotine, carbachol, and d-tubocurarine. [3H]QNB binding was competitively inhibited by atropine, pirenzepine, and carbachol. Hexamethonium did not affect the binding of either ligand. In competition experiments with [3H]QNB, pirenzepine recognized only one binding site with "low affinity," and carbachol recognized two sites with different affinities. beta-adrenergic receptors were present in a very low amount, whereas alpha-adrenergic and dopaminergic receptors were not detectable. IMR32 cells had an imipramine-sensitive [3H]dopamine uptake, but carbachol, high levels of K+, the calcium ionophore A23187, and alpha-latrotoxin were not able to induce release of [3H]dopamine that had been taken up. The ultrastructural analysis showed that IMR32 cells contained very few dense-core vesicles, suggesting a low storage capacity for neurotransmitter. These cells could be an useful in vitro model for studying neurotransmitter receptors of the human CNS.
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PMID:Pharmacological characterization of cholinergic receptors in a human neuroblastoma cell line. 371 5


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