Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The psychoactive properties of Cannabis sativa and its major biologically active constituent, delta 9-tetrahydrocannabinol, have been known for years. The recent identification and cloning of a specific cannabinoid receptor suggest that cannabinoids mimic endogenous compounds affecting neural signals for mood, memory, movement, and pain. Using whole-cell voltage clamp and the cannabinomimetic aminoalkylindole WIN 55,212-2, we have found that cannabinoid receptor activation reduces the amplitude of voltage-gated calcium currents in the neuroblastoma-glioma cell line NG108-15. The inhibition is potent, being half-maximal at less than 10 nM, and reversible. The inactive enantiomer, WIN 55,212-3, does not reduce calcium currents even at 1 microM. Of the several types of calcium currents in NG108-15 cells, cannabinoids predominantly inhibit an omega-conotoxin-sensitive, high-voltage-activated calcium current. Inhibition was blocked by incubation with pertussis toxin but was not altered by prior treatment with hydrolysis-resistant cAMP analogues together with a phosphodiesterase inhibitor, suggesting that the transduction pathway between the cannabinoid receptor and calcium channel involves a pertussis toxin-sensitive GTP-binding protein and is independent of cAMP metabolism. However, the development of inhibition is considerably slower than a pharmacologically similar pathway used by an alpha 2-adrenergic receptor in these cells. Our results suggest that inhibition of N-type calcium channels, which could decrease excitability and neurotransmitter release, may underlie some of the psychoactive effects of cannabinoids.
 ...
PMID:Cannabinoids inhibit N-type calcium channels in neuroblastoma-glioma cells. 131 42

Mouse neuroblastoma x rat glioma hybrid cells (N x G, 108CC15) were used to study the inhibitory effects of the synthetic opioid D-Ala2-D-Leu5-enkephalin (DADLE), somatostatin, adrenaline-alpha 2 and angiotensin II on voltage-dependent Ca(2+)-currents (ICa) using the patch-clamp technique in the whole-cell configuration mode. The inhibitory effects could be abolished by pretreatment of N x G cells with pertussis toxin or intracellular infusion of GDP beta S indicating an involvement of a pertussis toxin sensitive GTP-binding protein (G-protein), presumably Go. The effect of DADLE, the strongest inhibitor of ICa, was studied during dibutyryl cyclic AMP (dBcAMP) induced differentiation. Using omega-conotoxin GVIA (omega-CTX) and methoxyverapamil (D600) as specific Ca(2+)-channel blockers of the N- and L-type Ca(2+)-channels, it was found that in N x G cells DADLE predominantly induces inhibition of T- and N-type Ca(2+)-channels.
 ...
PMID:Inhibitory modulation of fast and slow Ca(2+)-currents in neuroblastoma x glioma cells during differentiation. 165 35

Long-term ethanol exposure is known to inhibit bradykinin-stimulated phosphoinositide hydrolysis in cultures of neuroblastoma x glioma 108-15 cells. In the present study, [3H]bradykinin binding, GTP-binding protein function, and phospholipase C activity were assayed in cells grown for 4 days in 100 mM ethanol with the aim of elucidating the molecular target of ethanol on signal transduction coupled to inositol trisphosphate and diacylglycerol formation. Ethanol exposure reduced guanosine 5'-O-(3-thiotriphosphate) [GTP(S)]- and, to a lesser extent, NaF/AlCl3-stimulated phosphoinositide hydrolysis, whereas it had no effect on the enzymatic activity of a phosphatidylinositol 4,5-bisphosphate-specific phospholipase C. [3H]Bradykinin binding in the absence of GTP(S) was not influenced by ethanol exposure. However, the reduction in [3H]bradykinin binding seen in control cells after addition of GTP analogue was inhibited in cells grown in ethanol-containing medium. The results indicate that long-term ethanol exposure exerts its effects on receptor-stimulated phosphoinositide hydrolysis primarily at the level of the GTP-binding protein.
 ...
PMID:G proteins coupled to phospholipase C: molecular targets of long-term ethanol exposure. 185 Dec 10

Acetylcholine (ACh) can inhibit calcium currents (ICa) in nerve cells by activating muscarinic ACh receptors (mAChR). There are several different genetic subtypes of mAChR. It is not known which subtype(s) are responsible for ICa inhibition. To resolve this issue, we measured ICa inhibition by ACh with patch-clamp recording, by using Ba2+ as charge carrier, in clones of NG108-15 neuroblastoma x glioma hybrid cells transfected with DNA for mAChRI, II, III and IV. Control (non-transfected) cells showed a mean maximum inhibition of peak ICa of 12.8 +/- 1.8% (n = 36) at 1 mM ACh. No consistent increase in inhibition was detected in vector-transfected cells, or in cells transformed to express mAChRI or mAChRIII. In contrast, inhibition was significantly increased in clones transformed to express mAChRII or mAChRIV. Inhibition was not correlated with the number of muscarinic receptors as determined by 3H-quinuclidinyl benzilate binding. Inhibition in both control and transfected cells was prevented by pretreatment with pertussis toxin (PTx). Inhibition persisted in the presence of extracellular or intracellular dibutyryl cyclic AMP, and hence is not because of inhibition of adenylate cyclase. We conclude that the inhibition of neuronal ICa is mediated preferentially by mAChRII and mAChRIV, via a PTx-sensitive GTP-binding protein.
 ...
PMID:Selective coupling of different muscarinic acetylcholine receptors to neuronal calcium currents in DNA-transfected cells. 198 Jul 42

The effect of GTP on Ca2+ uptake and release was studied in a microsomal fraction isolated from neuroblastoma x glioma hybrid NG108-15 cells. GTP did not alter the ATP-dependent initial uptake of Ca2+ but markedly enhanced the efflux of Ca2+ from microsomes. GTP-dependent Ca2+ release requires the presence of millimolar concentration of Mg2+. The effect of GTP was not mimicked by other nucleotides and was competitively blocked by the thiophosphate analogue of GTP, GTP gamma S but not by the non-hydrolyzable nucleotide GMP-PNP. Addition of an inhibiting concentration of GTP gamma S after completion of GTP-induced calcium release did not result in a re-uptake of Ca2+, showing the irreversibility of the releasing effect of GTP. Our data are consistent with the hypothesis of Ca2+-dependent GTP-induced opening of a channel responsible for vectorial transport of Ca2+ ions from one intracellular compartment to another. A model is proposed suggesting that the GTP-binding protein is a GTP-specific diacylglycerol kinase.
 ...
PMID:Evidence for a GTP-dependent increase in membrane permeability for calcium in NG108-15 microsomes. 251 40

Opiate receptor-mediated inhibition of adenylate cyclase activity was elicited in membranes of C6BUI glioma cells and S49 cyc- lymphoma cells after fusion with opiate receptor-containing membranes derived from NG108-15 neuroblastoma x glioma hybrid cells. The fusion was induced by polyethylene glycol using procedures developed by Orly and Schramm [(1976) Proc. Natl. Acad. Sci. USA 73, 4410-4414]. Prior to fusion, the adenylate cyclase activity of the donor. NG108-15 cell membrane, was inactivated by N-ethylmaleimide treatment. Prostaglandin E1 receptors and the stimulatory GTP-binding protein Ns were transferred to the recipient cells along with opiate receptors. Thus, inhibitory receptors can be transferred to foreign adenylate cyclase systems just as stimulatory receptors had earlier been found to do. Furthermore, opiate receptors have been shown to function in non-neuronal cells.
 ...
PMID:Transfer of functional opiate receptors from membranes to recipient cells by polyethylene glycol-induced fusion. 282 Aug 7

Stimulation of basal adenylate cyclase activity in membranes of neuroblastoma x glioma hybrid cells by prostaglandin E1 (PGE1) is half-maximal and maximal (about 8-fold) at 0.1 and 10 microM respectively. This hormonal effect requires GTP, being maximally effective at 10 microM. However, at the same concentrations that stimulate adenylate cyclase in the presence of GTP, PGE1 inhibited basal adenylate cyclase activity when studied in the absence of GTP, by maximally 60%. A similar dual action of PGE1 was observed with the forskolin-stimulated adenylate cyclase, although the potency of PGE1 in both stimulating and inhibiting adenylate cyclase was increased and the extent of stimulation and inhibition of the enzyme by PGE1 was decreased by the presence of forskolin. The inhibition of forskolin-stimulated adenylate cyclase by PGE1 occurred without apparent lag phase and was reversed by GTP and its analogue guanosine 5'-[gamma-thio]triphosphate at low concentrations. Treatment of neuroblastoma x glioma hybrid cells or membranes with agents known to eliminate the function of the inhibitory GTP-binding protein were without effect on PGE1-induced inhibition of adenylate cyclase. The data suggest that stimulatory hormone agonist, apparently by activating one receptor type, can cause both stimulation and inhibition of adenylate cyclase, and that the final result depends only on the activity state of the stimulatory GTP-binding protein, Gs. Possible mechanisms responsible for the observed adenylate cyclase inhibition by the stimulatory hormone PGE1 are discussed.
 ...
PMID:Guanine nucleotide-independent inhibition of adenylate cyclase by a stimulatory hormone. 305 32

Neuroblastoma-glioma NG108-15 cells that were cultured for 48 h with the opiate antagonist, naloxone, respond to the guanosine 5'-triphosphate (GTP) analogue guanosine 5'-[beta, gamma-imido]-triphosphate (GMP-PNP) in the binding assay as the control, non-treated, cells. This was observed when the guanyl nucleotide was tested in the presence or absence of sodium chloride and also after subcellular fractionation of the membranes on a sucrose gradient which separated between two receptor-containing fractions. The findings suggest that the increase in delta type enkephalin receptors in naloxone-treated NG108-15 cells does not reflect an alteration in the interaction between the receptor and the adenylate cyclase-GTP-binding protein system.
 ...
PMID:Up-regulation of opiate receptors by opiate antagonists in neuroblastoma-glioma cell culture: the possibility of interaction with guanosine triphosphate-binding proteins. 609 9

Monolayer cultures of neuroblastoma X glioma hybrid (clonal) cell line NG108-15, synchronized by the isoleucine/glutamine deprivation method, showed maximal expression of opiate binding sites at the same point in the cell cycle at which prostaglandin E1 (PGE1) had a maximum stimulatory effect on cyclic AMP synthesis. However, the capacity of enkephalin [D-Ala2D-Leu5] to block the stimulation of cyclic AMP synthesis by PGE1 was not related to the number of opiate receptors expressed. The Ki for the inhibition of cyclic AMP synthesis by opioid peptides increased substantially during the period of the cell cycle at which maximal expression of opiate binding sites occurred, making the effective level of inhibition of adenylate cyclase activity by 0.1 microM enkephalin [D-Ala2D-Leu5] the same through the cell cycle. Data are presented to suggest that enkephalin receptor coupling to adenylate cyclase, via a GTP-binding protein, is maximal during G1 phase (which may approximate the state of the differentiated neuron) and minimal during S + G2 phase, just prior to cell division, when many receptors are uncoupled.
 ...
PMID:Cell cycle-dependent expression of specific opiate binding with variable coupling to adenylate cyclase in a neurotumor hybrid cell line NG108-15. 631 83

We found in cultured glioma (C6BU-1) cells that excitatory amino acids (EAAs) such as glutamate, N-methyl-D-aspartate (NMDA), aspartate, and metabotropic glutamate receptor agonist trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylate caused an increase in the inositol 1,4,5-trisphosphate formation and the intracellular Ca2+ concentration ([Ca2+]i) in the absence of extracellular Mg2+ and Ca2+. Pertussis toxin treatment abolished this glutamate-induced [Ca2+]i increase. Various antagonists against NMDA receptor-ion channel complex, such as Mg2+, D-2-amino-5-phosphonovalerate (D-APV), HA-966, and MK-801, also inhibited the increase in [Ca2+]i induced by glutamate. These results indicate that these metabotropic EAA receptors coupled to pertussis toxin-susceptible GTP-binding protein and phospholipase C system in C6BU-1 glioma cells have the pharmacological properties of NMDA receptor-ion channel complexes. We also found that in the presence of Mg2+ these metabotropic receptors resemble the NMDA receptor-ion channel complex interacted with 5-hydroxytryptamine2 (5-HT2) receptor signaling. EAAs inhibited 5-HT2 receptor-mediated intracellular Ca2+ mobilization and inositol 1,4,5-trisphosphate formation in a concentration-dependent manner. The inhibitory effect of glutamate was reversed by various NMDA receptor antagonists (D-APV, MK-801, phencyclidine, and HA-966), but L-APV failed to block the inhibitory effect of glutamate. The same result was observed in the absence of extracellular Ca2+. In addition, this inhibitory effect on 5-HT2 receptor-mediated signal transduction was abolished by treatment of C6BU-1 cells with pertussis toxin, whereas 5-HT2 receptor-mediated [Ca2+]i increase was not abolished by pertussis toxin treatment. We can, therefore, conclude that the inhibitory effect of glutamate is not a result of the influx of Ca2+ through the ion channel and that it operates via metabotropic glutamate receptors, having NMDA receptor-ion channel complex-like properties and being coupled with pertussis toxin-sensitive GTP-binding protein and phospholipase C.
 ...
PMID:Metabotropic glutamate receptor in C6BU-1 glioma cell has NMDA receptor-ion channel complex-like properties and interacts with serotonin2 receptor-stimulated signal transduction. 752 90


1 2 Next >>