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

1. The role of cyclic ADP ribose and ryanodine receptors in the inhibition of the M-like current (IK(M,ng)) by acetylcholine was investigated in m1 muscarinic receptor-transformed mouse neuroblastoma-rat glioma hybrid (NG108-15) cells using patch-clamp techniques and calcium microfluorimetry. 2. Acetylcholine (1-100 microM) decreased IK(M,ng) by up to 55 %. Application, via the patch pipette, of the cyclic ADP ribose antagonists 8-amino-cyclic ADP ribose (10-100 microM) and 8-bromo-cyclic ADP ribose (100-1000 microM) reduced this inhibition of IK(M,ng) in a concentration-dependent manner. The half-maximal inhibition concentrations for 8-amino- cyclic ADP ribose and 8-bromo-cyclic ADP ribose were around 40 microM and 1 mM, respectively. 3. Neither of the cyclic ADP ribose antagonists altered the amplitude of IK(M,ng) per se, or the incidence of the concurrent Ca2+-activated K+ current (IIK(Ca)) activation, also mediated by acetylcholine. 4. The ryanodine receptor modulators ryanodine (1-10 microM) and Ruthenium Red (10 microM) did not alter IK(M,ng) amplitude or IK(M,ng) inhibition mediated by acetylcholine. There was a statistically significant increase in the proportion of cells showing outward currents in the presence of Ruthenium Red. 5. Intracellular calcium levels measured with fura-2 microfluorimetry were increased with low concentrations of ryanodine (1 microM), more consistently with caffeine (10 mM), and in almost every case with both bradykinin (300 nM) and acetylcholine (100 microM). Caffeine-, but not bradykinin-evoked responses were abolished by preincubation with ryanodine (10 microM). 6. The fast 'rundown rate' of the M-current recorded in rat superior cervical ganglion cells under whole-cell conditions precluded an investigation of the effects of intracellular dialysis of cyclic ADP ribose. However, when cyclic ADP ribose (5 microM) was applied directly to the cytoplasmic face of inside-out membrane patches excised from rat superior cervical ganglion cells containing M-channels, it had no effect on the main parameters of single channel activity (conductance, mean open time or frequency of opening). 7. These results indicate that cyclic ADP ribose acts on a specific intracellular site to mediate IK(M,ng) inhibition. However, unlike previously established effects of cyclic ADP ribose, the ryanodine receptor is not required, suggesting that another molecular target may be involved. Studies at the single channel level indicate that cyclic ADP ribose may not act directly on the M-channels in inside-out patches.
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PMID:The role of ryanodine receptors in the cyclic ADP ribose modulation of the M-like current in rodent m1 muscarinic receptor-transformed NG108-15 cells. 1043 36

Fast confocal laser-scanning microscopy was used to study spatiotemporal properties of IP(3)-mediated Ca(2+) release signals in human SH-SY5Y neuroblastoma cells. [Ca(2+)](i) increases were not affected by ryanodine (30 microgM) or caffeine (10 mM) and largely insensitive to removal of external Ca(2+), indicating predominance of IP(3)-induced Ca(2+) release. Ca(2+) signals evoked by high concentration (10 microM) of the muscarinic agonist carbachol appeared as self-propagating waves initiating in cell processes. At low carbachol concentrations (500 nM) Ca(2+) changes in most cells displayed striking spatiotemporal heterogeneity. The Ca(2+) response in the cell body was delayed and had a smaller amplitude and a slower rise time than that in processes. Ca(2+) changes in processes either occurred in a homogeneous manner throughout the whole process or were sometimes confined to hot spots. Regional differences in surface-to-volume ratio appear to be critical clues that determine the spatiotemporal pattern of intracellular Ca(2+) release signals.
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PMID:Mapping of IP(3)-mediated Ca(2+) signals in single human neuroblastoma SH-SY5Y cells: cell volume shaping the Ca(2+) signal. 1066 16

The immunophilin FKBP12 associates with intracellular Ca2+ channels and this interaction can be disrupted by the immunosuppressant FK506. We have investigated the effect of FK506 on Ca2+ release and Ca2+ uptake in permeabilized cell types. Changes in medium free [Ca2+] were detected by the fluorescent Ca2+ indicator fluo-3 in digitonin-permeabilized SH-SY5Y human neuroblastoma cells, DT40 and R23-11 (i.e. triple inositol 1,4,5-trisphosphate (IP3) receptor knockout cells) chicken B lymphocytes and differentiated and undifferentiated BC3H1 skeletal muscle cells. 45Ca2+ fluxes were studied in saponin-permeabilized A7r5 rat smooth muscle cells. Addition of FK506 to permeabilized SH-SY5Y cells led to a sustained elevation of the medium [Ca2+] corresponding to approximately 30 % of the Ca2+ ionophore A23187-induced [Ca2+] rise. This rise in [Ca2+] was not dependent on mitochondrial activity. This FK506-induced [Ca2+] rise was related to the inhibition of the sarcoplasmic/endoplasmic reticulum Ca2+-Mg2+-ATPase (SERCA) Ca2+ pump. Oxalate-facilitated 45Ca2+ uptake in SH-SY5Y microsomes was inhibited by FK506 with an IC50 of 19 microM. The inhibition of the SERCA Ca2+ pump was not specific since several macrocyclic lactone compounds (ivermectin > FK506, ascomycin and rapamycin) were able to inhibit Ca2+ uptake activity. FK506 (10 microM) did not affect IP3-induced Ca2+ release in permeabilized SH-SY5Y and A7r5 cells, but enhanced caffeine-induced Ca2+ release via the ryanodine receptor (RyR) in differentiated BC3H1 cells. In conclusion, FK506 inhibited active Ca2+ uptake by the SERCA Ca2+ pump; in addition, FK506 enhanced intracellular Ca2+ release through the RyR, but it had no direct effect on IP3-induced Ca2+ release.
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PMID:Effects of the immunosuppressant FK506 on intracellular Ca2+ release and Ca2+ accumulation mechanisms. 1085 21

Necdin, a growth suppressor expressed predominantly in postmitotic neurons, interacts with viral oncoproteins and cellular transcription factors E2F1 and p53. In search of other cellular targets of necdin, we screened cDNA libraries from neurally differentiated murine embryonal carcinoma P19 cells and adult rat brain by the yeast two-hybrid assay. We isolated cDNAs encoding partial sequences of mouse NEFA and rat nucleobindin (CALNUC), which are Ca(2+)-binding proteins possessing similar domain structures. Necdin interacted with NEFA via a domain encompassing two EF hand motifs, which had Ca(2+) binding activity as determined by (45)Ca(2+) overlay. NEFA was widely distributed in mouse organs, whereas necdin was expressed predominantly in the brain and skeletal muscle. In mouse brain in vivo, NEFA was localized in neuronal perikarya and dendrites. By immunoelectron microscopy, NEFA was localized to the cisternae of the endoplasmic reticulum and nuclear envelope in brain neurons. NEFA-green fluorescent protein (GFP) fusion protein expressed in neuroblastoma N1E-115 cells was retained in the cytoplasm and partly secreted into the culture medium. Necdin enhanced the cytoplasmic retention of NEFA-GFP and potentiated the effect of NEFA-GFP on caffeine-evoked elevation of cytosolic Ca(2+) levels. Thus, necdin and NEFA might be involved in Ca(2+) homeostasis in neuronal cytoplasm.
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PMID:The postmitotic growth suppressor necdin interacts with a calcium-binding protein (NEFA) in neuronal cytoplasm. 1091 98

Presynaptic varicosities of the model neuronal cell line NG108-15, a cholinergic neuroblastoma cell x glioma cell hybrid capable of innervating striated myotubes, were examined for the presence of inositol 1,4,5-trisphosphate (IP3)-sensitive and Ca2+-activated (ryanodine-sensitive) Ca2+ stores using confocal microscopic imaging of Ca2+-sensitive fluorescent dye loaded into the cells. Initial demonstration of the presence of IP3 receptors and ryanodine receptors in the NG108-15 varicosities was obtained using immunocytochemistry. Treatment of NG108-15 cells with bradykinin (0.1 microM), whose receptor is linked to IP3 generation, and separately, caffeine (10 mM), an activator of endoplasmic reticulum ryanodine receptors, resulted in substantial increases in [Ca2+]i in the varicosities. K+-evoked changes in [Ca2+]i in the varicosities were reduced (52 %) after emptying the ryanodine-sensitive Ca2+ store using caffeine (10 mM), but were not affected by prior depletion of the IP3-sensitive Ca2+ store using thapsigargin (1 microM). Bradykinin-induced changes in [Ca2+]i were abolished following depletion of the IP3-sensitive Ca2+ store using thapsigargin (1 microM) and were reduced (72 %) by prior emptying of the ryanodine-sensitive Ca2+ store with caffeine (10 mM). The same results were obtained when the varicosities of the NG108-15 cells had formed synaptic junctions with co-cultured rat hindlimb myotubes. Taken together, the results suggest that, in the varicosities, activation of the IP3 pathway evoked the release of Ca2+ from the IP3-sensitive store, which, in turn, secondarily induced the release of Ca2+ from the ryanodine-sensitive store via Ca2+-induced Ca2+ release, and that depolarization-induced Ca2+ entry evoked Ca2+-induced Ca2+ release only from the ryanodine-sensitive store. Thus, functional internal Ca2+ stores are inherent components of presynaptic varicosities in this neural cell line.
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PMID:Functional IP3- and ryanodine-sensitive calcium stores in presynaptic varicosities of NG108-15 (rodent neuroblastoma x glioma hybrid) cells. 1110 42

Caffeine is one of the most widely consumed neuroactive drugs, coming mostly from everyday beverages such as coffee and tea. To investigate whether caffeine induces apoptosis in the central nervous system, 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay, 4,6-diamidino-2-phenylindole (DAPI) staining, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, flow cytometric analysis, DNA fragmentation assay, and caspase-3 enzyme assay were performed on SK-N-MC human neuroblastoma cells. Cells treated with caffeine at concentrations as high as 10 mM exhibited several characteristics of apoptosis. In addition, caffeine was shown to increase the caspase-3 activity. These results suggest that high-dose of caffeine induces apoptosis in human neuroblastoma cells, probably by increasing the caspase-3 enzyme activity.
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PMID:Caffeine induces apoptosis in human neuroblastoma cell line SK-N-MC. 1237 22

The identification of a second 5-HT(3) (5-HT(3B)) subunit provides an explanation for 5-HT(3) receptor heterogeneity. We investigated whether introduction of recombinant 5-HT(3B) subunits would alter the functional properties of mouse neuroblastoma 5-HT(3) receptors. RT-PCR analysis revealed that NB41A3 cells contain mRNAs encoding 5-HT(3A) and 5-HT(3B) subunits. 5-HT increased intracellular Ca(2+) concentration ([Ca(2+)](i)) and caused the concentration-dependent activation of inward currents recorded at -60 mV. Both actions of 5-HT were antagonized by ondansetron. The 5-HT concentration-response relationship of NB41A3 cells was indistinguishable from that of the related NG108-15 cell line. The selective 5-HT(3)-receptor agonist mCPBG also elevated [Ca(2+)](i) and activated inward currents. 2-M-5HT was less efficacious than 5-HT as an activator of 5-HT(3) receptors in NB41A3 cells and did not significantly increase [Ca(2+)](i). The 5-HT induced increase in [Ca(2+)](i) did not involve caffeine- or thapsigargin-sensitive intracellular Ca(2+) stores. The introduction of the 5-HT(3B) subunit by transient transfection of NB41A3 cells caused 5-HT to become less potent as an activator of 5-HT(3) receptors and altered the kinetics of 5-HT activated currents so that they resembled currents mediated by 5-HT(3AB) receptors. The 5-HT(3B) subunit also abolished the 5-HT induced [Ca(2+)](i) increase seen in untransfected NB41A3 cells. These data are consistent with the hypothesis that NB41A3 cells predominantly express homomeric 5-HT(3A) receptors that become heteromeric 5-HT(3AB) receptors upon introduction of the recombinant 5-HT(3B) subunit.
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PMID:Introduction of the 5-HT3B subunit alters the functional properties of 5-HT3 receptors native to neuroblastoma cells. 1262 20

Nitric oxide (NO) is a potent activator of the p53 tumor suppressor protein. However, the mechanisms underlying p53 activation by NO have not been fully elucidated. We previously reported that a rapid downregulation of Mdm2 by NO may contribute to the early phase of p53 activation. Here we show that NO promotes p53 nuclear retention and inhibits Mdm2-mediated p53 nuclear export. NO induces phosphorylation of p53 on serine 15, which does not require ATM but rather appears to depend on the ATM-related ATR kinase. An ATR-kinase dead mutant or caffeine, which blocks the kinase activity of ATR, effectively abolishes the ability of NO to cause p53 nuclear retention, concomitant with its inhibition of p53 serine 15 phosphorylation. Of note, NO enhances markedly the ability of low-dose ionizing radiation to elicit apoptotic killing of neuroblastoma cells expressing cytoplasmic wild-type p53. These findings imply that, through augmenting p53 nuclear retention, NO can sensitize tumor cells to p53-dependent apoptosis. Thus, NO donors may potentially increase the efficacy of radiotherapy for treatment of certain types of cancer.
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PMID:Nitric oxide promotes p53 nuclear retention and sensitizes neuroblastoma cells to apoptosis by ionizing radiation. 1271 24

In the present study, it was investigated whether 1,2-bis(2-aminophenoxy)ethane-N,N,N'N'-tetraacetic acid (BAPTA-AM), an intracellular Ca(2+) chelator, possesses protective effect against caffeine-induced apoptosis in the central nervous system. Through morphological and biochemical analyses, cells treated with caffeine exhibited several apoptotic features. On the other hand, cells treated with caffeine and BAPTA-AM, showed decreased occurrence of apoptotic features. In addition, it was shown that BAPTA-AM treatment inhibits caffeine-induced increase of caspase-3 enzyme activity. These results show that caffeine induces apoptotic death in human SK-N-MC neuroblastoma cells and BAPTA-AM prevents apoptosis by attenuating caffeine-induced caspase-3 activation.
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PMID:1,2-bis(2-aminophenoxy)ethane-N,N,N'N'-tetraacetic acid (BAPTA-AM) inhibits caffeine-induced apoptosis in human neuroblastoma cells. 1503 13

In human SH-SY5Y neuroblastoma cells, two distinct intracellular Ca2+ stores, a KCl-/caffeine-sensitive and a carbachol-/IP3-sensitive store, were demonstrated previously. In this study, responses of these two intracellular Ca2+ stores to thapsigargin were characterized. Ca2+-release from these stores was evoked either by high K+ (100 mM KCl) or by 1 mM carbachol, and changes in the intracellular Ca2+ level were monitored using Fura-2 fluorimetry. A sequential stimulation protocol (KCl-->carbachol or vice versa) allowed evaluation of the individual contribution of different Ca2+ stores to the evoked intracellular Ca2+ ([Ca2+]i)-transients and the dynamic interaction between them. Thapsigargin (0.05 nM - 20 microM) alone induced a [Ca2+]i-transient. Both the carbachol- and the KCl-evoked [Ca2+]i-transients were inhibited by thapsigargin, but with very different sensitivities. Thapsigargin inhibited the carbachol-evoked [Ca2+]i-transients with (IC50 = 0.353 nM) or without (IC50 = 0.448 nM) a KCl-prestimulation, but an additional small component, with a much lower sensitivity (IC50=4814 nM), was observed in the absence of a KCl-prestimulation. In contrast, the KCl-evoked [Ca2+]i-transients displayed only one component with a very low sensitivity to thapsigargin in both absence (IC50=3343 nM) and presence (IC50=6858 nM) of a carbachol-prestimulation. These findings suggest that the sarco-/endoplasmic reticular Ca2+ ATPases associated with the KCl-/caffeine- and carbachol-/IP3-sensitive intracellular Ca2+ stores differ from each other, either in types or in their post-translational modification. Such difference might play important role in the regulation of neuronal Ca2+ homeostasis.
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PMID:Differential thapsigargin-sensitivities and interaction of Ca2+ stores in human SH-SY5Y neuroblastoma cells. 1515 4


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