Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of dihydroergocristine on energy metabolism was studied in the isolated perfused rat brain affected by ischemia and in cultivated C-1300 neuroblastoma cells deprived of oxygen and glucose. Creatine phosphate, ATP, ADP, AMP, glucose, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-diphosphate, pyruvate, and lactate were measured enzymatically. After a perfusion period of 30 min, the cortex of the isolated perfused rat brain exhibited an energy state not different from that in vivo. Dihydroergocristine added to the perfusion medium (5 mumol/L) did not influence these substrate levels under normal perfusion conditions. However, this drug was able to retard the breakdown of high-energy phosphates during ischemia and to accelerate the restoration of the energy state during the postischemic reperfusion period. The perfusion rate was not changed by the drug, and therefore it was assumed that dihydroergocristine could act directly on cell metabolism. This view was supported by the results obtained from experiments using cultivated N-2a neuroblastoma cells. These cells were incubated in a buffered salt solution deprived of glucose and oxygen for 15 min. Under these conditions, dihydroergocristine (2 mumol/L) added to the incubation medium caused changes in the concentrations or the high-energy phosphates similar to those in the isolated brain preparation: It increased the ATP concentration and decreased the ADP concentration significantly.
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PMID:Effect of dihydroergocristine on energy metabolism studied in the isolated perfused rat brain affected by ischemia and in neuroblastoma cells deprived of oxygen and glucose. 643 25

Incubation of purified rat brain tubulin with cholera toxin and radiolabeled [32P] or [8-3H]NAD results in the labeling of both alpha and beta subunits as revealed on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Treatment of these protein bands with snake venom phosphodiesterase resulted in quantitative release of labeled 5'-AMP, respectively labeled with the corresponding isotope. Two-dimensional separation by isoelectric focusing and SDS-PAGE of labeled and native tubulin revealed that labeling occurs at least in four different isotubulins. The isoelectric point of the labeled isotubulins was slightly lower than that of native purified tubulin. This shift in mobility is probably due to additional negative charges involved with the incorporation of ADP-ribosyl residues into the tubulin subunits. SDS-PAGE of peptides derived from [32P]ADP-ribosylated alpha and beta tubulin subunits by Staphylococcus aureus protease cleavage showed a peptide pattern identical with that of native tubulin. Microtubule-associated proteins (MAP1 and MAP2) of high molecular weight were also shown to undergo ADP-ribosylation. Incubation of permeated rat neuroblastoma cells in the presence of [32P]NAD and cholera toxin results in the labeling of only a few cell proteins of which tubulin is one of the major substrates.
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PMID:ADP-ribosylation of microtubule proteins as catalyzed by cholera toxin. 676 71

There has been an exponential growth in interest in purinoceptors since the potent effects of purines were first reported in 1929 and purinoceptors defined in 1978. A distinction between P1 (adenosine) and P2 (ATP/ADP) purinoceptors was recognized at that time and later, A1 and A2, as well as P2x and P2y subclasses of P1 and P2 purinoceptors were also defined. However, in recent years, many new subclasses have been claimed, particularly for the receptors to nucleotides, including P2t, P2z, P2u(n) and P2D, and there is some confusion now about how to incorporate additional discoveries concerning the responses of different tissues to purines. The studies beginning to appear defining the molecular structure of P2-purinoceptor subtypes are clearly going to be important in resolving this problem, as well as the introduction of new compounds that can discriminate pharmacologically between subtypes. Thus, in this review, on the basis of this new data and after a detailed analysis of the literature, we propose that: (1) P2X(ligand-gated) and P2Y(G-protein-coupled) purinoceptor families are established; (2) four subclasses of P2X-purinoceptor can be identified (P2X1-P2X4) to date; (3) the variously named P2-purinoceptors that are G-protein-coupled should be incorporated into numbered subclasses of the P2Y family. Thus: P2Y1 represents the recently cloned P2Y receptor (clone 803) from chick brain; P2Y2 represents the recently cloned P2u (or P2n) receptor from neuroblastoma, human epithelial and rat heart cells; P2Y3 represents the recently cloned P2Y receptor (clone 103) from chick brain that resembles the former P2t receptor; P2Y4-P2Y6 represent subclasses based on agonist potencies of newly synthesised analogues; P2Y7 represents the former P2D receptor for dinucleotides. This new framework for P2 purinoceptors would be fully consistent with what is emerging for the receptors to other major transmitters, such as acetylcholine, gamma-aminobutyric acid, glutamate and serotonin, where two main receptor families have been recognised, one mediating fast receptor responses directly linked to an ion channel, the other mediating slower responses through G-proteins. We fully expect discussion on the numbering of the different receptor subtypes within the P2X and P2Y families, but believe that this new way of defining receptors for nucleotides, based on agonist potency order, transduction mechanisms and molecular structure, will give a more ordered and logical approach to accommodating new findings. Moreover, based on the extensive literature analysis that led to this proposal, we suggest that the development of selective antagonists for the different P2-purinoceptor subtypes is now highly desirable, particularly for therapeutic purposes.
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PMID:Purinoceptors: are there families of P2X and P2Y purinoceptors? 772 57

The present article investigates chronic opioid regulation of the stimulatory adenylate cyclase-coupled prostaglandin E1 (PGE1) receptor system in neuroblastoma x glioma (NG108-15) hybrid cells. Persistent activation of delta-opioid receptors by morphine (10 mumol/L; 3 days) substantially down-regulates the number of PGE1 binding sites by approximately 30%, without affecting their affinity. Radioligand binding studies performed in the presence of GTP gamma S (100 mumol/L) further revealed that the remaining PGE1 binding sites are still capable of interacting functionally with their associated stimulatory G proteins, Gs. On the postreceptor level, neither changes in the abundance nor in the intrinsic activity of the alpha subunit of Gs (Gs alpha) were found during the state of opioid dependence, as has been verified by western blot and S49 cyc- reconstitution experiments, respectively. Evaluation of the functional interaction between PGE1 receptors and Gs by means of receptor-stimulated, cholera toxin-catalyzed ADP-ribosylation of Gs alpha revealed a significant increase in the ability of PGE1 receptors to activate Gs alpha (3.3-fold increase in EC50; p < 0.05) in cells chronically exposed to morphine. This effect was completely blocked by coincubation of the cells together with the opiate antagonist naloxone (100 mumol/L; 3 days), whereas precipitation of morphine withdrawal by naloxone (100 mumol/L) had no further effect on sensitization in PGE1 receptor/Gs coupling. These findings provide evidence that the stimulatory adenylate cyclase-coupled PGE1 receptor system represents a potential target of chronic delta-opioid receptor activation in NG108-15 hybrid cells. They further suggest that sensitization in stimulatory signal transduction plays a critical role in the generation of opioid dependence.
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PMID:Chronic activation of inhibitory delta-opioid receptors cross-regulates the stimulatory adenylate cyclase-coupled prostaglandin E1 receptor system in neuroblastoma x glioma (NG108-15) hybrid cells. 776 24

The mechanism by which cyclic GMP synthesis is activated through a nucleotide receptor was studied in mouse neuroblastoma x rat glioma hybrid cells [108CC15 (NG 108-15)]. The transient increase in cyclic GMP level induced by ATP reached its maximum at 20 s and lasted for approximately 1 min. The maximal rise in cyclic GMP level achieved was highest for ATP and decreased in the following order: ATP = adenosine 5'(gamma-thio)triphosphate > UTP = 2-methylthio-ATP > ADP much greater than CTP, AMP, alpha,beta-methylene-ATP, 2'- and 3'-O-(4-benzoylbenzoyl)ATP. The EC50 of 1 +/- 0.2 microM for UTP was significantly lower than that for ATP (14 +/- 8 microM) and for all the other nucleotides tested. The rank order of potency is consistent with the pharmacology of a P2u receptor. At submaximal concentrations of the nucleotides ATP and UTP, the rise in cyclic GMP level was inhibited by suramin (IC50 = 40-60 microM) or the pyridoxal phosphate analogue pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (IC50 = 20-30 microM). Pretreatment of cells with the Ca2+ ionophore ionomycin or with 2,5-di(tert-butyl)-1,4-benzohydroquinone, an inhibitor of Ca(2+)-ATPase in the endoplasmic reticulum, a maneuver to deplete internal Ca2+ stores, suppressed the ATP- or UTP-induced stimulation of cyclic GMP synthesis. Similarly, loading of the cells with the Ca2+ chelator 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid inhibited cyclic GMP formation by ATP. Preincubation with forskolin to raise the cyclic AMP level potentiated the ATP-induced rise in cyclic GMP level by 60%.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ca(2+)- and nitric oxide-dependent stimulation of cyclic GMP synthesis in neuronal cell line induced by P2-purinergic/pyrimidinergic receptor. 779 51

Monoclonal antibodies were produced that are specific for the three major pertussis toxin-sensitive G protein alpha-subunits present in mammalian brain--alpha o, alpha i1, and alpha i2--using purified bovine brain G proteins, purified rat brain G proteins, and purified recombinant alpha i2, respectively. These monoclonal antibodies were used to monitor changes in the concentrations of the three G protein alpha-subunits during differentiation of PC12 cells and human neuroblastoma LA-N-5 cells. In PC12 cells, levels of alpha i1 but not alpha i2 increased during nerve growth factor-induced differentiation. In contrast, alpha i2 but not alpha i1 increased when LA-N-5 cells were differentiated with retinoic acid. The concentration of alpha o increased in both cell lines during differentiation. Electrophoretic resolution of alpha o subtypes revealed that although alpha o2 was the major subtype in undifferentiated cells, only the concentration of alpha o1 increased during differentiation of both PC12 and LA-N-5 cells. The level of 43-kDa growth-associated protein, a protein known to associate with alpha o, increased similarly to that of alpha o1. ADP-ribosylation of alpha o, alpha i1, and alpha i2 with pertussis toxin did not alter the reactivities of the monoclonal antibodies, but toxin treatment of cells reduced the concentrations of each protein after 24 h. There was no change in the concentration of alpha q, which is not ADP-ribosylated by pertussis toxin. Thus, these new monoclonal antibodies enabled the detection of differential increases in subtypes of alpha i and alpha o associated with neuronal differentiation.
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PMID:Pertussis toxin-sensitive G protein alpha-subunits: production of monoclonal antibodies and detection of differential increases on differentiation of PC12 and LA-N-5 cells. 786 Nov 41

A phospholipase-C-linked nucleotide receptor, sensitive to both uridine and adenosine triphosphate (UTP and ATP) has been cloned from NG108-15 neuroblastoma x glioma hybrid cells. We have tested whether activation of this receptor could inhibit the voltage-dependent K+ current [IK(M) or "M-current"] in NG108-15 cells recorded using whole-cell patch-clamp methods. Both UTP and ATP inhibited IK(M) by 44% and 42%, respectively, at 100 microM. Mean IC50 values were: UTP, 0.77 +/- 0.27 microM; ATP, 1.81 +/- 0.82 microM. The order of nucleotide and nucleoside activity at 100 microM was: UTP = ATP > ATP [gamma S] = ITP > 2-MeSATP > ADP = GTP >> AMP-CPP, adenosine, where ATP[gamma S] is adenosine 5'-O-(3-thiotriphosphate), ITP is inosine 5'-triphosphate, 2-MeSATP is 2-methylthio ATP and AMP-CPP is alpha, beta methylene ATP. This rank order accords with their activities at the cloned P2U receptor. Effects were not inhibited by suramin (up to 500 microM) or by pre-incubation for 12 h in 500 ng.ml-1 Pertussis toxin. Inhibition of IK(M) was frequently preceded by a transient outward current, probably a Ca(2+)-activated K+ current, responding to Ca2+ mobilization. No effect on the delayed rectifier K+ current was observed. These observations match those expected from stimulating other phospholipase-C-linked receptors in NG108-15 cells.
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PMID:Activation of nucleotide receptors inhibits M-type K current [IK(M)] in neuroblastoma x glioma hybrid cells. 789 8

The efficiency of ion-pair reversed-phase HPLC on a Vydac C18 column with 50 mM ammonium acetate (pH 4.75)-methanol-acetonitrile (88:9:3, v/v/v) as the mobile phase with isocratic separation and fluorescence detection for the determination of cAMP in cellular extracts was evaluated. This method was compared with a radioimmunoassay technique in terms of linearity, reproducibility and sensitivity. No interactions with other nucleotides such as AMP, ADP, ATP and cGMP were observed. Application to the measurement of cAMP modifications was studied in a neuroblastoma cell line: LA-N-2 cells stimulated by a neuropeptide, vasoactive intestinal peptide.
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PMID:High-performance liquid chromatographic determination of cyclic 3',5'-AMP with fluorescence detection. Vasoactive intestinal peptide-induced modification of its concentration in neuroblastoma cells. 795 67

The susceptibility of various lines of cultured cells to botulinum ADP-ribosyltransferase, known as C3 exoenzyme, was examined. Human neuroblastoma GOTO cells were most sensitive. The C3 exoenzyme caused a change in cell shape that involved extension of neurites. The exoenzyme evoked the outgrowth of neurites from chick ganglion as effectively as nerve growth factor, suggesting that C3 exoenzyme possesses neurotropic activity. Experiments with 125I-labeled enzyme revealed that C3 exoenzyme was rapidly incorporated into cells but the number of incorporated enzyme molecules was small. Once C3 exoenzyme had been incorporated, ADP-ribosylation of the substrate (Rho protein) in GOTO cells occurred immediately and rapidly reached a maximum level. However, some of Rho proteins remained unmodified even after induction of the change in morphology. These findings suggest that ADP-ribosylation by C3 exoenzyme is directly associated with the differentiation of GOTO cells but that other events may also participate in this process.
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PMID:Morphological effects, rate of incorporation, and the enzymatic action of botulinum ADP-ribosyltransferase, known as C3 exoenzyme, on human neuroblastoma GOTO cells. 796 71

High performance liquid chromatography of nucleotides from Triton X-100 cytoskeletal extracts has permitted analysis of the ATP and ADP content of actin filaments isolated intact from PC12 pheochromocytoma cells. We observed that the adenine nucleotide content matched the actin content of these cytoskeletal extracts, a finding consistent with the unit stoichiometry of nucleotide binding. Efficient assembly-linked ATP hydrolysis occurs in vivo, and based on a boundary hydrolysis model for nucleotide-promoted assembly, the observed ADP/ATP ratio indicates that the average microfilament in nonmuscle cells has 2-4 ATP-actin molecules at its growing end. Studies with NB41A3 neuroblastoma cells indicate that the ATP content of assembled actin filaments is about 3-4 times lower.
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PMID:Phosphorylation states of actin filament adenine nucleotides in detergent-extracted neuronal cytoskeletal fractions. 802 94


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