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)

A comparison was made of ethanol's effects on the order of plasma membranes in intact cells and some isolated membrane preparations. Order was assessed by steady-state fluorescence polarization techniques using the non-permeant probe, TMA-DPH. The data show that two cultured cells, rat neonatal astroglial and N2A neuroblastoma, were sensitive to significant ethanol-induced disordering within the anesthetically relevant range (100 - 200 mM). Human erythrocytes, cultured fibroblasts and homogenized astroglial cells required higher ethanol concentrations (greater than 250 mM) to produce a similar effect. Intact erythrocytes were approximately twice as sensitive as erythrocyte ghost membranes to ethanol-induced perturbation. The neonatal glial and N2A cells were approximately five times more sensitive than synaptic membranes to ethanol effects. DMPC and DMPC + cholesterol liposomes and myelin membranes were insensitive to ethanol's effects. The incorporation of 10 mole % ganglioside GM1 sensitized the liposomes to ethanol-induced perturbation.
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PMID:On the sensitivity of intact cells to perturbation by ethanol. 261 59

One of the biochemical results of ethanol exposure is a change in the amount of the intracellular second messenger cyclic AMP (cAMP) produced in response to receptor stimulation. In general, acute ethanol exposure increases the amount of cAMP produced on stimulation of receptors coupled to the enzyme adenylyl cyclase via the GTP-binding protein Gs, whereas chronic ethanol exposure has the opposite effect (results for receptors coupled via Gi have been more variable). We previously reported that adaptation to continuous ethanol exposure reduces receptor-stimulated cAMP production by 25-35% in a neuroblastoma cell line (NG108-15), and an even greater reduction of 75% was observed in lymphocytes taken from actively-drinking alcoholics. This reduction in receptor-stimulated cAMP levels was recently confirmed in platelets from alcoholics. None of these studies, however, determined whether more than one receptor coupled to adenylyl cyclase activity was affected in the same cell. Here we report that chronic ethanol exposure causes desensitization of heterologous receptors coupled to Gs as cAMP production mediated by prostaglandin E1 as well as by adenosine is reduced by approximately 30% in NG108-15 cells. We show that, after chronic ethanol exposure, the activity of the alpha subunit of Gs is decreased by 29%, the amount of alpha s protein is decreased by 38.5%, and alpha s messenger RNA is decreased by 30%. Thus, cellular adaptation to ethanol involves a reduction in alpha s mRNA and, as a consequence, reduced cAMP production by heterologous receptors coupled to Gs. Such changes in cAMP production may account for the tolerance and physical dependence on ethanol in alcoholism.
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PMID:Chronic ethanol causes heterologous desensitization of receptors by reducing alpha s messenger RNA. 283 57

A cDNA library was efficiently synthesized from mouse neuroblastoma poly(A)+RNA. Several modifications of the oligo(dC)(dG) tailing procedure were used. After first strand synthesis, a dATP tail was added to the 3'-end of the cDNA. The second strand was primed for synthesis with oligo(dT). Blunt ends were produced on the cDNA by treatment with S1 nuclease. Size-enriched fractions of high molecular weight DNAs were obtained by passing the cDNA over a Sepharose CL-4B column. The optimal tailing time for each cDNA fraction was individually tested. Tailing reactions used terminal deoxynucleotidyl transferase and annealing reactions used a (G)-tailed Pst I cut pBR322. E. coli K12 RR1 cells were transformed and 2.5-5 X 10(6) transformants per microgram cDNA insert were obtained for each size fraction. The transformants had an average insert size of 1200 base pairs and were 98% ampicillin sensitive. Our modifications in the method for cDNA library synthesis had 3 advantages. (1) Homopolymer-primed cDNA treated with S1 nuclease allowed the blunt ends to be tailed synchronously. This allowed a higher transformation efficiency without loss of 5'-sequences. (2) Time tailing determined the most efficient tail length and optimized the transformation efficiency in each size fraction. (3) A Sephadex G-50 mini-column was used to desalt and dry nitrogen was used to concentrate the ds cDNA instead of the usual ethanol precipitation. This resulted in almost 100% recovery of synthesized products at each step of this procedure.
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PMID:High-efficiency cloning of DNA sequences complementary to mouse neuroblastoma polyadenylated RNA. 286 33

The acute effects of ethanol were studied on the guanylate cyclase system of cultured murine neuroblastoma clone N1E-115. Using intact cells, we found that although ethanol had no effect on basal levels of cyclic GMP synthesis, it rapidly inhibited in a concentration-dependent manner cyclic GMP synthesis mediated by the agonists histamine (histamine H1 receptor) and carbachol (low-affinity muscarinic receptor) and by ionophore X537A and melittin, agents which bypass these receptors. At 200 mM ethanol, inhibition was about 40 to 50% with the agonists, X537A and melittin. Ethanol had no effect on the high-affinity muscarinic receptor, that mediates inhibition of cyclic AMP synthesis. With carbachol ethanol's inhibition was reversible and was a mixed competitive/noncompetitive type. For a series of alcohols, inhibitory potency with carbachol correlated with chain length directly. In addition, sucrose and sodium chloride, which like ethanol increases the osmolality of the incubation medium, mimicked the effects of ethanol. In a crude cellular homogenate, ethanol and other alcohols inhibited both basal and sodium nitroprusside-stimulated guanylate cyclase activity. The effect of ethanol on basal enzyme activity was noncompetitive. Thus, the inhibition by ethanol and other alcohols of receptor-mediated cyclic GMP synthesis appears to be at the level of guanylate cyclase.
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PMID:Acute effects of ethanol and other short-chain alcohols on the guanylate cyclase system of murine neuroblastoma cells (clone N1E-115). 286 20

With the use of cultured murine neuroblastoma cells (clone N1E-115), the authors studied the effects of chronic ethanol on prostaglandin E, (PGE1)-mediated cyclic AMP formation, adenylate cyclase activity and [3H]PGE1 binding. Whereas acute exposure of these cells to ethanol potentiates the PGE1 response, exposure of cells, for as little as 1 day, to 100 mM ethanol resulted in a diminished responsiveness to PGE1 compared with that in acutely treated cells. This apparent tolerance was well developed by day 4, and, by day 7, treated cells had a diminished response to PGE1 when assayed in the absence of ethanol. To achieve the same level of PGE1-mediated cyclic AMP synthesis as acutely exposed cells, chronically exposed cells required higher concentrations of ethanol. With 7 to 10 days of treatment, there was a modest (10-13%) increase in basal, PGE1- and forskolin-stimulated adenylate cyclase activity in membranous preparations, a 28 to 40% increase in high-affinity [3H]PGE1 binding to membranes with no change in Kd or in the ability of 5'-guanylimidodiphosphate to reduce this binding and a 155% increase in [3H]PGE1 binding to intact cells with no change in Kd. Thus, chronic exposure of N1E-115 cells to ethanol resulted in tolerance to its effects on the PGE1 receptor system, and this tolerance was accompanied by apparently paradoxical changes in PGE1-stimulated cyclic AMP synthesis and [3H]PGE1 binding.
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PMID:Effects of chronic exposure to ethanol on the prostaglandin E1 receptor-mediated response and binding in a murine neuroblastoma clone (N1E-115). 287 32

Forskolin, a diterpene activator of adenylate cyclase, stimulated the formation of cyclic AMP in intact murine neuroblastoma clone N1E-115 cells and stimulated adenylate cyclase activity in a membranal preparation from these cells. Ethanol caused a concentration-dependent inhibition of the forskolin-stimulated responses in both preparations. In intact cells, the inhibition appeared to be noncompetitive. However, in the membranal preparation the inhibition was more of a competitive nature. In addition, there was also a large difference in the amount of inhibition in the two systems. Thus, the inhibition by ethanol was nearly twice as much with intact cells as with membranes. Sucrose appeared to mimic these effects of ethanol, suggesting that with intact cells the effect of this alcohol may be due, in part, to changes in cellular osmotic pressure.
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PMID:Inhibition by ethanol of forskolin-stimulated adenylate cyclase in a murine neuroblastoma clone (N1E-115). 299 55

Ethanol inhibits opioid peptide binding to the delta-opioid receptor. When neuroblastoma x glioma NG108-15 hybrid cells are grown with 25-200 mM ethanol, opioid receptor density increases up to 2-fold without a change in receptor affinity. Since changes in neurotransmitter receptor density may be important in neuronal adaptations to ethanol, we investigated the underlying mechanisms and functional consequences of this phenomenon. The opiate antagonist, naloxone, also increased opioid receptor number, but produced a smaller effect than ethanol with greater fractional inhibition of binding; long term enhancement of binding by ethanol is therefore not a simple function of acute receptor inhibition. Ethanol did not inhibit receptor down-regulation by etorphine, an opiate agonist, and therefore is not likely to increase receptor expression through interference with tonic down-regulation by endogenous opioid peptides. Ethanol increased opioid receptor expression in NG108-15 cells treated with actinomycin D, but not cycloheximide; hence, normal protein synthesis, but not DNA transcription, may be required for this response. The opioid receptors induced in ethanol-treated cells were subject to normal up-regulation by naloxone, down-regulation by etorphine, and acute inhibition of agonist binding by Na+. Etorphine maximally inhibits cyclic AMP accumulation in NG108-15 cells with only fractional occupancy of opioid receptors. Chronic ethanol exposure increased the receptor reserve for this response, resulting in a 3.5-fold increase in the potency of etorphine for inhibiting phenylisopropyladenosine-stimulated cyclic AMP accumulation. Neuronal adaptation to ethanol may involve changes in the density of receptors that regulate cellular levels of cyclic AMP.
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PMID:Ethanol increases the expression of functional delta-opioid receptors in neuroblastoma x glioma NG108-15 hybrid cells. 300 82

The acute and chronic neurologic effects of ethanol appear to be due to its interaction with neural cell membranes. Chronic exposure to ethanol induces changes in the membrane that lead to tolerance to the effects of ethanol. However, the actual membrane changes that account for tolerance to ethanol are not understood. We have developed a model cell culture system, using NG108-15 neuroblastoma-glioma hybrid cells, to study cellular tolerance to ethanol. We have found that adenosine receptor-stimulated cAMP levels increased markedly upon acute exposure to ethanol. However, the cells became tolerant to ethanol, since chronically treated cells required ethanol to maintain normal adenosine-stimulated cAMP levels. Moreover, the cells appeared to be dependent on ethanol, as evidenced by reduced adenosine-stimulated cAMP levels in the absence of ethanol. Recovery occurred after ethanol was withdrawn. These cellular changes appear to parallel the clinical events of acute ethanol intoxication, tolerance, and dependence.
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PMID:Ethanol regulation of adenosine receptor-stimulated cAMP levels in a clonal neural cell line: an in vitro model of cellular tolerance to ethanol. 300 52

Long-term incubation of clonal neural cell lines with ethanol differentially reduces the stimulation of cAMP accumulation by hormones and cholera toxin. In the NG108-15 neuroblastoma chi glioma hybrid cell line, this heterologous desensitization was associated with a 42% reduction in the expression of Gs alpha and no significant change in Gi alpha. By contrast, ethanol treatment of the parental neuroblastoma cell line N18TG2 caused little loss of response to hormones or cholera toxin and no significant change in Gs alpha or Gi alpha. Ethanol induced heterologous desensitization in N1E-115 neuroblastoma cells; however, this cell line showed a dose-dependent increase in Gi alpha and a later decrease in Gs alpha. Thus, ethanol causes heterologous desensitization of hormone-stimulated cAMP accumulation by different mechanisms in related neural cell lines.
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PMID:Ethanol differentially regulates G proteins in neural cells. 313 33

Two neuroglial cell lines (U-251 MG and C6) had a substantial capacity to convert ethanol to acetate in vitro largely by an alcohol dehydrogenase (ADH)-independent mechanism and three neuroblastoma cell lines (IMR-32, NB41A3, and Neuro-2a) had a lesser but significant ethanol-metabolizing capacity which was also either partly or largely ADH-independent. The ADH-independent pathway of ethanol metabolism by neural cells appeared to be dependent on one or more isoenzymes of cytochrome P-450. The data emphasize the possibility that the neurotoxicity of ethanol may be related to a relatively high ethanol-metabolizing capability of neural tissue and particularly of neuroglial cells.
Alcohol Clin Exp Res 1987 Jun
PMID:Neuroglial and neuroblastoma cell lines are capable of metabolizing ethanol via an alcohol-dehydrogenase-independent pathway. 330 84


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