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

We have recently identified and sequenced the cDNA for an opioid-binding protein with homologies to cell adhesion molecules (OBCAM) (Schofield, P. R., McFarlard, K. C., Hayflick, J. S., Wilcox, J. N., Cho, T. M., Roy, S., Lee, N. M., Loh, H. H., and Seeburg, P. H. (1989) EMBO J. 8, 489-495). Several lines of evidence using antibodies suggest that OBCAM may play a functional role in NG108-15 neuroblastoma x glioma cells, a useful model system that contains a homogeneous population of delta-opioid receptors. A logical extension of this research is to further test this hypothesis. As part of this study, NG108-15 cells were stably transfected with either sense or antisense sequences of a portion of pROM, the rat cDNA for OBCAM. [3H] Diprenorphine binding was greatly reduced in antisense-transfected cells relative to non-transfected cells. Binding to alpha 2-adrenergic, muscarinic, and insulin receptors was unaffected. These results further support the notion that OBCAM or its analogue is part (or a subunit) of an opioid receptor. Furthermore, our observation of an apparently specific reduction in opioid binding in these transfected cells suggests that they may provide a novel genetic approach for studying regulation of the opioid receptor in this defined cell line.
 ...
PMID:Specific reduction of delta-opioid receptor binding in transfected NG108-15 cells. 131 12

Five separate guanine nucleotide-binding proteins (G proteins) were immunologically identified in membranes from neuroblastoma x glioma NG108-15 hybrid cells. These alpha subunit proteins were Gi2 alpha, two isoforms of Gi3 alpha, and two isoforms of Go alpha. The G proteins that interacted with delta-opioid receptors in these membranes were identified using cholera toxin (CTX)-induced ADP-ribosylation and antisera selective for various G protein alpha subunits. In the presence of delta-opioid agonists, CTX induced the incorporation of [32P]ADP-ribose into three pertussis toxin substrates. Using antisera generated against peptide sequences from G alpha subunits, these three pertussis toxin substrates were identified as Gi2 alpha, Go2 alpha, and one isoform of Gi3 alpha, which has yet to be identified. This CTX-induced labeling was demonstrated to be mediated via the delta-opioid receptor in these hybrid cells by the observation that delta agonists D-Ala2-D-Leu5-enkephalin (DA-DLE) and D-Pen2-D-Pen5-enkephalin, as well as the nonselective agonists etorphine and bremazocine, were active, but the mu agonist PL017 and the kappa agonist U-50-488H did not show this activity. This incorporation into all three substrates induced by DADLE was dose dependent, with EC50 (95% confidence interval) values ranging from 12 (3-52) to 183 (65-520) nM, which compared with the Kd value of 10 +/- 1.5 nM for this agonist, a dose that produces maximal inhibition of adenylate cyclase activity. Furthermore, pretreatment of the cells with pertussis toxin or treatment of the membranes with the antagonist naloxone blocked the incorporation induced by DADLE. Incorporation of [32P]ADP-ribose into all three substrates decreased 35-83% in membranes in which the receptors had been down-regulated by chronic treatment of the cells with DADLE. Thus, a single opioid receptor type can interact with three separate G proteins.
 ...
PMID:Identification of three separate guanine nucleotide-binding proteins that interact with the delta-opioid receptor in NG108-15 neuroblastoma x glioma hybrid cells. 131

Neuroblastoma x glioma NG 108-15 hybrid cells contain a homogeneous population of delta-opioid receptors. NG 108-15 membranes were labelled either with the opiate agonist, [3H]etorphine or the opiate antagonist [3H]diprenorphine under various conditions: absence or presence of Na+ and/or 5'-guanylylimidophosphate (GppNHp). Ultracentrifugation in linear sucrose gradients after digitonin solubilization of prelabeled receptor was performed. In the soluble extracts from NG 108-15 hybrid cell membranes, bound [3H]etorphine and bound [3H]diprenorphine sedimented in the same position, even in the presence of NaCl and/or GppNHp. These data were analyzed in terms of relative agonist potency of diprenorphine on this specific model, using equilibrium binding studies and inhibition of adenylate cyclase activity. Diprenorphine, at the concentrations used for sedimentation studies, behaving as an opiate antagonist, it is concluded that the delta-opioid receptor could be strongly precoupled to the G-protein in the NG 108-15 cell.
 ...
PMID:The delta-opioid receptor in neuroblastoma x glioma NG 108-15 hybrid cells is strongly precoupled to a G-protein. 132 7

The F11 cell line is a fusion product of cells of mouse neuroblastoma cell line N18TG-2 with embryonic rat dorsal-root ganglion (DRG) neurons. Previous biochemical results suggest that they express mu- and delta-opioid receptors that are negatively coupled to adenylate cyclase. The present study provides direct agonist-binding and electrophysiologic evidence of mu and delta, but not kappa, receptor expression in F11 cells. Radioligand binding assays show that F11 cell membranes bind the mu- and delta-opioid receptor agonists, DAGO and DPDPE with Kd = 4.5 and 4.9 nM and Bmax = 111 and 195 fmol/mg, respectively. Tight-seal patch-clamp recordings of F11 cells after several days in a differentiating culture medium (low serum, cyclic AMP and nerve growth factor) showed that: (i) the outward K+ current during pulsed depolarization in most of these cells was increased by either DAGO or DPDPE, but none were responsive to both opioids or to the kappa-opioid receptor agonist, U-50,488H. The response was blocked by relevant receptor antagonists, naloxone, beta-funaltrexamine or naltrindole; (ii) cells without processes responded neither to DAGO nor to DPDPE; (iii) treatment with pertussis toxin blocked all opioid-induced increases in outward K+ current. The opioid-induced increase in voltage-dependent membrane K+ current in F11 cells resembles the inhibitory effect elicited by mu- and delta-opioid agonists in primary cultures of mouse DRG neurons.
 ...
PMID:F11 neuroblastoma x DRG neuron hybrid cells express inhibitory mu- and delta-opioid receptors which increase voltage-dependent K+ currents upon activation. 133 Feb 16

Protein kinase C (PKC) activation was examined for its role in delta-opioid receptor down-regulation in the neuroblastoma X glioma hybrid cell line NG108-15. Incubation of NG108-15 cells for 2 hr at 37 degrees with up to 1 microM 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (PMA), a phorbol ester that activates PKC, had no effect on opioid binding to membranes prepared from these cells. However, as little as 3 nM PMA incubated with an opioid agonist and NG108-15 cells potentiated the decrease and the rate of decrease of opioid binding, compared with agonist alone. Scatchard analysis of [3H][D-Ala2,D-Leu5]enkephalin (DADLE) binding revealed that NG108-15 cells incubated for 3 hr with 1 nM DADLE and 30 nM PMA displayed a > 50% reduction in the number of [3H]DADLE binding sites with no affinity change at the remaining sites, compared with cells treated with DADLE alone. The antagonist naloxone blocked both DADLE-induced and PMA-enhanced DADLE-induced down-regulation. The agonists morphine and cyclazocine, which alone were unable to induce delta receptor down-regulation, did so in the presence of PMA. The PKC inhibitor staurosporine and down-regulation of PKC by chronic PMA treatment blocked PMA potentiation of DADLE-induced down-regulation, but not "normal" DADLE-induced down-regulation. The enhancement of down-regulation by PMA was unaffected by either metabolic inhibitor or incubations at 20 degrees, conditions that blocked down-regulation by DADLE alone. NG108-15 cells incubated with [3H]DADLE and PMA retained more [3H]DADLE than cells incubated with [3H]DADLE alone, suggesting that PMA enhanced receptor internalization instead of merely inhibiting membrane binding. The diacylglycerol 1-oleoyl-2-acetyl-glycerol and bradykinin substituted for PMA but not carbachol, indicating that PKC activated physiologically may play a role in delta receptor down-regulation.
 ...
PMID:Protein kinase C activation increases the rate and magnitude of agonist-induced delta-opioid receptor down-regulation in NG108-15 cells. 133 57

The affinity cross-linking of the delta-opioid receptor in neuroblastoma x glioma NG108-15 cells was undertaken using (3-[125I]iodotyrosyl27)human-beta-endorphin ([125I]beta-endorphin) and disuccinimidyl suberate (DSS) or bis(sulfosuccinimidyl) suberate (BS3) in order to estimate molecular size. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, two radioactive bands were observed. Labeling of a major band of 29 kDa diminished in the presence of unlabeled selective delta-opioid agonist, [D-Pen2,D-Pen5]enkephalin (DPDPE), in a concentration-dependent manner, while labeling of a minor band of 58 kDa was hardly affected. The labeling intensity of the 29 kDa band decreased by addition of guanosine 5'-(3-o-thio)triphosphate (GTP gamma S) or by pretreatment of cells with pertussis toxin. These results, taking the molecular weight of covalently bound beta-endorphin (3.6 kDa) into consideration, suggest that the delta-opioid receptor in NG108-15 cell membrane is a 25 kDa protein which is coupled to pertussis toxin-sensitive guanosine triphosphate-binding proteins (G-proteins).
 ...
PMID:Affinity cross-linked delta-opioid receptor in NG108-15 cells is low molecular weight (25 kDa) and coupled to GTP-binding proteins. 133 16

The human SH-SY5Y neuroblastoma cell line displays morphological, neurochemical, and electrophysiological characteristics of sympathetic neurons. mu-Opioid receptors mediate inhibition of the N-type calcium current present in these cells. Here we have studied the effects of chronic incubation with morphine (1 microM for 3-7 days) in vitro on the inhibition of this current induced by mu-opioid agonists and noradrenaline. In untreated control cells the mu-opioid agonists and noradrenaline. In untreated control cells the mu-opioid agonists morphine (1 microM) and [D-Ala2,N-MePhe4,Gly-ol] enkephalin (DAMGO) (10 nM to 1 microM), and noradrenaline (10 nM to 10 microM) inhibited the calcium current to a similar extent. The maximal effects of DAMGO and noradrenaline were not additive. Chronic exposure to morphine had no effect on the maximum amplitude of the calcium current evoked or on its voltage sensitivity. However, the concentration-response curve to DAMGO was shifted to the right in a parallel manner, with a 7-fold increase in the IC50 value but no change in the maximum inhibition produced. In contrast, the maximum inhibition in response to morphine appeared to be substantially reduced. Noradrenaline inhibited the calcium current equally in untreated and morphine-tolerant cells. Thus, it is concluded that morphine-induced tolerance to inhibition of the N-type calcium current occurs at the single-cell level and is homologous to the mu-opioid receptor. Also, morphine appears to be an agonist of lower efficacy than DAMGO. The results are consistent with tolerance being due to a functional reduction in the mu-opioid receptor reserve, probably by disruption of the receptor/GTP-binding protein interaction.
 ...
PMID:Mu-opioid receptor inhibition of calcium current: development of homologous tolerance in single SH-SY5Y cells after chronic exposure to morphine in vitro. 166 36

We have recently demonstrated that acute and chronic treatments with estradiol and progesterone induce changes in the responsiveness of endogenous opioid systems to painful stimulation. In the present study the neuroblastoma SH-SY5Y subclone known to contain predominantly mu opioid receptors was used as a model to characterize the gonadal steroid effect on this opioid receptor system. The function of opioid receptors was assessed by measuring prostaglandin E1 (PGE1)-induced cyclic AMP accumulation after various treatments with estradiol and progesterone. Differentiated SH-SY5Y cells respond to PGE1 with a dramatic increase in cAMP level. Morphine (MOR) inhibits by about 75% the stimulatory effect of PGE1 on cAMP. Pretreatment with 5 nM of estradiol for 6 days resulted in a significant increase of PGE1-stimulated cAMP accumulation. Exposure of cells for 48 h to estradiol in doses of 5 nM or 50 nM did not affect cell sensitivity to the PGE1 effect on cAMP. Moreover, neither dose of estradiol changed the inhibitory effect of morphine on PGE1-induced cAMP response. There was a significant increase in PGE1-stimulated cAMP accumulation after treatment with 100 nM progesterone for 1 h or 15 min and a marked elevation of cAMP levels was also measured after 15 min treatment with 10 nM progesterone. Exposure to either dose of progesterone for 8 h, 48 h or 6 days did not affect basal or PGE1-induced cAMP in neuroblastoma cells. Progesterone-treated groups responded to MOR with 56-67% inhibition of PGE1-stimulated cAMP accumulation. The potency of MOR-induced inhibition was comparable to the MOR effect in cells not treated with the steroid.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:cAMP accumulation in opioid-sensitive SH-SY5Y neuroblastoma cells is modified by estradiol and progesterone. 166 75

The predominant consequences of mu-opioid-receptor activation are depression of both neuronal activity and transmitter release. Mu-Opioid agonists have previously been observed to increase a potassium conductance and to inhibit adenylate cyclase. We now report that activation of mu-opioid receptors directly decreases the N-type calcium-channel current in a differentiated, human neuroblastoma cell line (SH-SY5Y). The coupling between the mu-opioid receptor and the calcium channel involves a pertussis toxin-sensitive G protein and is independent of changes in adenylate cyclase activity. The inhibition of the calcium-channel current is voltage dependent because it is largely overcome by strong membrane depolarization. It is not associated with changes in the kinetics of current inactivation. Therefore, the mu-receptor belongs to the superfamily of G-protein-coupled, inhibitory neurotransmitter receptors which modulate the activity of calcium and potassium channels and adenylate cyclase.
 ...
PMID:Mu-opioid-receptor-mediated inhibition of the N-type calcium-channel current. 167 47

The human neuroblastoma clonal cell line SH-SY5Y expresses both mu- and delta-opioid receptors (ratio approximately 4.5:1). Differentiation with retinoic acid (RA) was previously shown to enhance the inhibition of adenylyl cyclase (AC) by mu-opioid agonists. We tested here the inhibition of cyclic AMP (cAMP) accumulation by morphine under a variety of conditions: after stimulation with prostaglandin E1 (PGE1), forskolin, and vasoactive intestinal peptide (VIP), both in the presence and in the absence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). Morphine inhibition of the forskolin cAMP response (approximately 65%) was largely unaffected by the presence of IBMX. In contrast, deletion of IBMX enhanced morphine's inhibition of the PGE1 and VIP cAMP response from approximately 50 to approximately 80%. The use of highly mu- and delta-selective agents confirmed previous results that inhibition of cAMP accumulation by opioids is mostly mu, and not delta, receptor mediated in SH-SY5Y cells, regardless of the presence or absence of IBMX. Because of the large morphine inhibition and the high cAMP levels even in the absence of IBMX, PGE1-stimulated, RA-differentiated SH-SY5Y cells were subsequently used to study narcotic analgesic tolerance and dependence in vitro. Upon pretreatment with morphine over greater than or equal to 12 h, a fourfold shift of the PGE1-morphine dose-response curve was observed, whether or not IBMX was added. However, mu-opioid receptor number and affinity to the mu-selective [D-Ala2, N-Me-Phe4, Gly5-ol]enkephalin were largely unaffected, and Na(+)- and guanyl nucleotide-induced shifts of morphine-[3H]naloxone competition curves were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Regulation of cyclic AMP by the mu-opioid receptor in human neuroblastoma SH-SY5Y cells. 169 94


1 2 3 4 5 6 7 8 9 10 Next >>