Effect of ryanodine on histamine release from rat peritoneal mast cells induced by anti-IgE.

Ryanodine strongly inhibited histamine release from rat peritoneal mast cells induced by anti-IgE. Ryanodine also inhibited Ca(2+)-mobilization from the intracellular Ca(2+)-store as well as histamine release in mast cells activated by anti-IgE. These results suggest that the effect of ryanodine on histamine release from rat mast cells might be due to the inhibition of Ca2+ release from the intracellular Ca2+ store.     

Effects of C18 Fatty Acids on Intracellular Ca2+ Mobilization and Histamine Release in RBL-2H3 Cells

To investigate the underlying mechanisms of C18 fatty acids (stearic acid, oleic acid, linoleic acid and α-linolenic acid) on mast cells, we measured the effect of C18 fatty acids on intracellular Ca²⁺ mobilization and histamine release in RBL-2H3 mast cells. Stearic acid rapidly increased initial peak of intracellular Ca²⁺ mobilization, whereas linoleic acid and α-linolenic acid gradually increased this mobilization. In the absence of extracellular Ca²⁺, stearic acid (100 µM) did not cause any increase of intracellular Ca²⁺ mobilization. Both linoleic acid and α-linolenic acid increased intracellular Ca²⁺ mobilization, but the increase was smaller than that in the presence of extracellular Ca²⁺. These results suggest that C18 fatty acid-induced intracellular Ca²⁺ mobilization is mainly dependent on extracellular Ca²⁺ influx. Verapamil dose-dependently inhibited stearic acid-induced intracellular Ca²⁺ mobilization, but did not affect both linoleic acid and α-linolenic acid-induced intracellular Ca²⁺ mobilization. These data suggest that the underlying mechanism of stearic acid, linoleic acid and α-linolenic acid on intracellular Ca²⁺ mobilization may differ. Linoleic acid and α-linolenic acid significantly increased histamine release. Linoleic acid (C18:2: ω-6)-induced intracellular Ca²⁺ mobilization and histamine release were more prominent than α-linolenic acid (C18:3: ω-3). These data support the view that the intake of more α-linolenic acid than linoleic acid is useful in preventing inflammation.     

Effect of dantrolene on histamine release from rat peritoneal mast cells.

Dantrolene strongly and dose-dependently inhibited histamine release from rat peritoneal mast cells induced by anti-IgE. Dantrolene inhibited Ca(2+)-mobilization from intracellular Ca(2+)-store as well as histamine release in mast cells activated by anti-IgE, the effect on both these phenomena being closely correlated. These results suggested that the effect of dantrolene on histamine release from rat mast cell might be due to the inhibition of Ca(2+)-release from intracellular Ca(2+)-store.     

Characterization of the prostaglandin E receptor expressed on a cultured mast cell line,BNu-2c13

Interleukin 3-dependent BNu-2c13 mast cells, mucosal type-like mast cells, exhibited a specific high-affinity binding site for [³H]prostaglandin (PG) E₂. The binding was completely displaced by M&B 28767, an EP₃-selective agonist, but not by EP₁- or EP₂-selective ligands, indicating that the PGE₂ binding site is of the EP₃ subtype PGE receptor. Whereas the EP₃ subtype is presumed to be coupled to inhibition of adenylate cyclase in various tissues and cells, in BNu-2c13 cells PGE₂ had no ability to inhibit adenylate cyclase activity, while it induced concentration-dependent stimulation of phosphoinositide metabolism and caused an increase in the intracellular free Ca²⁺ concentration in a pertussis toxin-sensitive manner. PGE₂ by itself did not evoke histamine release from the cells, but it markedly stimulated histamine release in concert with ionomycin, a Ca²⁺ ionophore. The PGE₂-stimulated release was also comletely blocked by pertussis toxin. Thus, the PGE receptor expressed on BNu-2c13 mast cells is of the EP₃ subtype and is linked to phosphoinositide metabolism via a pertussis toxin-sensitive G protein, and this activation leads to histamine release.     

Effect of the tridecamer of compound 48/80, a Ca2+-dependent histamine releaser,on phospholipid metabolism during the early stage of histamine release from rat mast cells

When the tridecamer component of compound 48/80 (Fraction D, Fr. D), a Ca²⁺-dependent histamine releaser, was incubated with rat mast cells that had been prelabeled with [³²P]phosphate, [³H]inositol or [³H]glycerol, it induced a rapid decrease in [³²P]phosphatidylinositol-4,5-bisphosphate (PIP₂) followed by increases of [³H]inositol-1,4,5-triphosphate (Ins P₃) and [³H]diacylglycerol during the 10 sec prior to detectable histamine release. Fr.D-induced changes of the metabolism of these compounds occurred even in the absence of Ca²⁺, but to a lesser extent than in the presence of Ca²⁺. In contrast, the accumulation of [³H]arachidonic acid into phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidic acid (PA) in [³H]arachidonic acid-prelabeled mast cells was Ca²⁺-dependently stimulated by Fr.D with a concomitant decrease in [³H]phophatidylethanolamine (PE). These Ca²⁺-dependent changes in PC and PE were not observed in mast cells preloaded with [³²P]phosphate, while [³²P]PI and [³²P]PA increased Ca²⁺ independently. Fr.D also increased ⁴⁵Ca²⁺ uptake by mast cells within 5 sec after the stimulation. These results indicate that Fr.D binding to mast cell Ca²⁺ independently induces rapid changes of PI cycle-related metabolism of plasma membrane components, while it also induces Ca²⁺-dependent accumulation of arachidonic acid into PC, PI and PA in association with the decrease of PE, which may be important during the latent period prior to the Ca²⁺-dependent release of histamine from Fr.D-stimulated mast cells.     

Plasma membrane adenosine triphosphatases in rat peritoneal mast cells and macrophages--the relation of the mast cell enzyme to histamine release.

Adenosine triphosphatases activated by calcium or magnesium have been demonstrated on the outer surface of rat peritoneal mast cells and macrophages. The plasma membrane ATPases in the two types of cells have similar but not identical properties. Mg²⁺ is somewhat more effective than Ca²⁺ in stimulating both the enzymes. They are not influenced by sodium and potassium and not inhibited by ouabain and oligomycin. Ethacrynic acid inhibits both, but the mast cell enzyme is more sensitive to it. The enzyme on the macrophage has five to thirty-seven times higher activity (average seventeen times) than that on the mast cell. The apparent K_m of the enzymes in intact cells, incubated with adenosine triphosphate for 5 min, is estimated to be 36 μM for mast cells and 30 μM for macrophages. The optimal pH for the mast cell and the macrophage enzymes is 6.7 and 7.1 respectively. The activities of the two enzymes rise similarly with temperature up to 37° but differ at 47°, the macrophage enzyme being less active at this temperature than at 37°. Phosphatidyl serine, which stimulates anaphylactic and dextran-induced histamine release, causes about 40 per cent stimulation of the plasma membrane ATPase of mast cells in the absence of Ca²⁺ and Mg²⁺ but has no appreciable effect in their presence. No change in the mast cell enzyme could, however, be observed in relation to histamine release induced by dextran, compound $\text{48}\text{80}$ and ATP. But ethacrynic acid, which in 1 mM concentration inhibits 50 per cent of the mast cell enzyme activity, also causes pronounced inhibition of histamine release induced by all the three agents in the same concentration. The inhibition is not influenced by the presence of glucose, suggesting that ethacrynic acid does not inhibit histamine release by blocking energy metabolism. Ethacrynic acid apparently acts at another site. The site of action could very well be plasma membrane ATPase. There is also a correlation between the inhibition of the mast cell enzyme by sodium fluoride and lack of calcium and their inhibitory effect on histamine release. The possible involvement of the plasma membrane ATPase of mast cells in the process of exocytosis leading to histamine release is discussed.     

Mechanism of action of disodium cromoglycate--mast cell calcium ion influx after a histamine-releasing stimulus.

Rat peritoneal mast cells release histamine and accumulate ⁴⁵Ca in a dose-dependent manner when concentrations of compound 48/80 ranging from 0·1 to 1·0 μg/ml are incubated with suspensions of the cells for 5 min at 37°. Influx of ⁴⁵Ca stimulated by compound 48/80 can be inhibited to varying degrees by prior addition of disodium cromoglycate. Inhibition was dependent on the concentration of both disodium cromoglycate and compound 48/80. The electrokinetic properties of intact rat mast cells are described; disodium cromoglycate caused a plasma membrane alteration possibly related to Ca²⁺ influx. Cromoglycate increased mast cell electrophoretic mobility but decreased the electrophoretic mobility of rat erythrocytes. The net electrophoretic mobility was a function of terminal sialic acid residues, ionic strenght, and pH. Binding of disodium cromoglycate to Ca²⁺ could not be demonstrated by a variety of sensitive physical techniques. The data support the theory that secretion of mast cell histamine is coupled to Ca²⁺ influx. It is suggested that disodium cromoglycate prevents mast cell histamine release by a plasma membrane alteration which prevents an increase in membrane permeability to Ca²⁺ stimulated by compound 48/80.     

Latrotoxin-induced exocytosis in mast cells transfected with latrophilin

α-Latrotoxin (α-LTX) is known to cause massive exocytosis from presynaptic nerve terminals. We investigated the effects of α-LTX on exocytotic release from mast cells, typical non-neuronal secretory cells. When we transfected mast cells with latrophilin, a specific receptor for α-LTX, α-LTX caused intracellular Ca²⁺ to increase and led to exocytosis in the presence of extracellular Ca²⁺. On the other hand, neither Ca²⁺ increase nor exocytosis was observed in the absence of extracellular Ca²⁺. These results indicate that α-LTX, together with latrophilin, works as a Ca²⁺ ionophore. However, α-LTX had additional effects on signal transduction in mast cells. We found that inhibitors of protein kinase C (PKC) partially suppressed exocytosis. Furthermore, several soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, including SNAP-23, were phosphorylated by α-LTX. These results suggest that exocytosis induced by α-LTX can be explained by (1) elevation of intracellular Ca²⁺, (2) phosphorylation of SNARE proteins including SNAP-23, syntaxin-4 and VAMP-8 through PKC-dependent and -independent pathways. Our study may provide a new system to investigate the action of α-LTX and the mechanism of exocytosis in mast cells.     

Differences in requirements and actions of various histamine-releasing agents.

Histamine release induced by dextran, concanavalin A (con A), antigen, anti-IgE, the ionophore A23187, somatostatin, compound 48/80, polylysine, and protamine was studied in Sprague-Dawley rat mast cells. Release by dextran, con A, antigen, and anti-IgE was highly dependent on addition of phosphatidyl serine (PS). The same agents plus A23187 were highly dependent on exogenous Ca²⁺ , but only dextran was completely dependent. The other (basic) agents showed little or no dependence on exogenous PS or Ca²⁺. Addition of 0.1 mM Mn²⁺ with the A23187 (in the presence of 1.0 mM Ca²⁺), which probably markedly reduced the level of the A23187-Ca complex, did not greatly educe release by the A23187. Treatment of the cells with neuraminidase increased release by con A, A23187, and antigen; did not greatly affect release by dextran; and definitely decreased release by 48/80, polylysine, and protamine. Each agent desensitized the cells to a higher concentration of the same agent, and most also reduced release by other agents. A23187 and protamine sometimes sensitized to each other, however, and dextran and antigen regularly sensitized to A23187. The observations indicate that the different agents did not act in an identical manner.     

Regulation of immunoglobulin E-mediated secretion by protein phosphatases in human basophils and mast cells of skin and lung.

A wide range of serine/threonine protein phosphatase (PP) inhibitors were studied for effects on the immunoglobulin E (IgE)-mediated release of histamine from human lung mast cells, human skin mast cells and basophils. Okadaic acid (OA) inhibited the release of histamine from all three cell types in a concentration-dependent manner. Two structural analogues of okadaic acid, okadaol and okadaone, known to be less active than the parent molecule as inhibitors of PP, were less active than okadaic acid as inhibitors of histamine release in these three cell types. A number of PP inhibitors, showing differences in selectivity for PP1 and PP2A, were also evaluated. Calyculin, which is roughly equipotent as a PP1 and PP2A inhibitor, attenuated the release of histamine from all three cell types. Similarly, tautomycin (TAU), which shows greater selectivity for PP1 over PP2A, was also effective at inhibiting histamine release in all three cell types. In contrast, fostriecin, which is very much more potent as an inhibitor of PP2A over PP1, was ineffective as an inhibitor in all three cell types. These data indicate that the regulation of mediator release by PPs is similar in lung mast cells, skin mast cells and basophils. Moreover, the data suggest that PP1 is important in the control of cellular activity.     

钾通道开放剂拮抗4-氨基吡啶诱发大鼠肥大细胞释放组胺

4-氨基吡啶(4-AP)能诱发大鼠腹腔肥大细胞(PMC)释放组胺,且呈浓度依赖关系。钾通道开放剂二氮嗪(Dia),米诺地尔(Min)及钙拮抗剂硝苯啶(Nif)均能明显抑制4-AP诱发大鼠PMC释放组胺。实验结果提示,大鼠肥大细胞膜上可能存在钾通道,4-AP可能通过阻滞钾通道,使钙通道开放,Ca²⁺内流增加而促进组胺释放,钾通道开放剂可能是一类新的组胺释放拮抗剂。     

The actions of retinal and retinoic acid on histamine release from rat peritoneal mast cells

Histamine release from rat peritoneal mast cells induced by anti-IgE was potentiated by the retinoids: retinoic acid 2-10 microM and retinal 1-5 microM. Retinal also produced a concentration-dependent increase in anti-IgE-stimulated 45Ca uptake by these mast cells. A similar potentiating action of both retinoids was observed on histamine release induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). For both anti-IgE- and TPA-induced histamine release, the potentiating effect of the two retinoids was only observed in the presence of extracellular calcium. In contrast, histamine release induced by compound 48/80 was inhibited by retinal 1-5 microM and by retinoic acid 10-50 microM and the inhibition was the same in the presence as in the absence of extracellular calcium 1 mM. Histamine release induced by calcium and the calcium ionophore A 23187 was inhibited by retinoid acid 2-10 microM and by retinal 10 microM. Inhibitions of compounds 48/80-induced histamine release by cromoglycate and by retinal were additive. It is concluded that while the actions of retinoids on rat peritoneal mast cells are consistent with the inhibition of protein kinase C, another action of these compounds, unrelated to this enzyme, may explain the data.     

Marine brevetoxin induces IgE-independent mast cell activation

Brevetoxins (PbTx) are sodium channel neurotoxins produced by the marine dinoflagellate Karenia brevis during red tide blooms. Inhalation of PbTx in normal individuals and individuals with pre-existing airways disease results in adverse airway symptoms including bronchoconstriction. In animal models of allergic inflammation, inhalation of PbTx results in a histamine H₁-mediated bronchoconstriction suggestive of mast cell activation. How mast cells would respond directly to PbTx is unknown. We thus explored the activation of mouse bone marrow–derived mast cells (BMMCs) following exposure to purified PbTx-2. Following in vitro exposure to PbTx-2, we examined cellular viability, mast cell degranulation (β-hexosaminidase release), intracellular Ca²⁺ and Na⁺ flux, and the production of inflammatory mediators (IL-6). PbTx-2 induced significant cellular toxicity within 24 h as measured by LDH release and Annexin-V staining. However, within 1 h of exposure, PbTx-2 induced BMMC degranulation and an increase in IL-6 mRNA expression independent of the high-affinity IgE receptor (FcεRI) stimulation. Activation of BMMCs by PbTx-2 was associated with altered intracellular Ca²⁺ and Na⁺ levels. Brevenal, a naturally produced compound that antagonizes the activity of PbTx, prevented changes in intracellular Na⁺ levels but did not alter activation of BMMCs by PbTx-2. These findings demonstrate that PbTx-2 activates mast cells independent of FcεRI providing insight into critical events in the pathogenesis and a potential therapeutic target in brevetoxin-induced airway symptoms.     

4-氨基吡啶诱发组胺释放及某些药物的拮抗作用

4-氨基吡啶(4-AP)有组胺释放作用。小鼠ip4-AP5mg·kg^-1后,肺中组胺含量明显减低,血中组胺含量显著增高。钙拮抗剂硝苯啶、TMB-8及钾通道开放剂米诺地尔均能明显抑制4-AP诱发的小鼠PMC释放组胺。结果提示,MC可能存在钾通道,4-AP诱发MC释放组胺可能与它阻滞钾通道,从而使钙通道开放,增加Ca²⁺内流有关。     

Physiological concentrations of zinc inhibit the release of histamine from human basophils and lung mast cells

We have previously shown that physiological concentrations of zinc (congruent to 7 X 10(-6) M) inhibit the release of histamine from human basophil leukocytes (Marone et al., J. Pharmacol. Exp. Ther. 217: 292, 1981). In these experiments we compared the effect of zinc chloride on the release of chemical mediators from human basophils and mast cells isolated from human lung. Preincubation (5 min, 37 degrees C) of human basophils and lung mast cells with zinc chloride (10(-6)-3 X 10(-5) M) caused dose-related inhibition of histamine and peptide leukotriene C4 (LTC4) release induced by anti-IgE. Increase Ca2+ concentrations (0.3 to 6 mM) in the extracellular medium completely reversed the inhibitory effect of zinc on anti-IgE-mediated histamine secretion. Zinc chloride was a competitive antagonist of the action of Ca2+ in histamine secretion induced by anti-IgE with a dissociation constant (Kd) of about 10(-5) M in both the basophil and mast cell systems. Thus physiological concentrations of zinc inhibit the release of histamine from human basophils and lung mast cells, presumably by blocking Ca2+ uptake induced by anti-IgE activation.     

The effect of acteoside on intracellular Ca2+ mobilization and phospholipase C activity in RBL-2H3 cells stimulated by melittin

This study was performed to investigate the effects of acteoside on various cellular functions such as, intracellular Ca²⁺ mobilization, phospholipase C activity, and exocytosis induced by melittin. Melittin (0.1–1 μM) dose-dependently increased intracellular Ca²⁺ mobilization in the presence of extracellular Ca²⁺, but was not affected by 1 μM U73122, a specific PLC inhibitor. In the absence of extracellular Ca²⁺, melittin (1 μM) did not induce a change in intracellular Ca²⁺ mobilization, which suggests that melittin-induced intracellular Ca²⁺ mobilization may be dependent on the influx of extracellular Ca²⁺ rather than on the release of intracellular Ca²⁺ storage. Acteoside (10 μM) significantly inhibited 1 μM melittin-induced Ca²⁺ mobilization by 33 %. In [³H]inositol-labeled cells, 1 μM melittin did not increase inositol phosphate formation, but more than 5 μM melittin significantly increased inositol phosphate formation, which was significantly inhibited by acteoside. Melittin (1 μM) significantly increased histamine release from RBL 2H3 cells in the presence or absence of extracellular Ca²⁺. Acteoside significantly inhibited 1-μM-melittin-induced histamine release by 74 % in the presence of extracellular Ca²⁺ and by 71 % in the absence of extracellular Ca²⁺. These data suggest that the inhibitory effect of acteoside on 1 μM-melittin-induced histamine release may be related to blockage of the calcium-independent pathway. Taken together, these data suggest that melittin has an influence on cellular functions such as intracellular Ca²⁺ mobilization, the PLC pathway, and exocytosis via various independent signalling pathways in RBL-2H3 cells, and was significantly inhibited by acteoside.     

Intracellular Ca2+ mediates lipoxygenase-induced proliferation of U-373 MG human astrocytoma cells

The role of intracellular Ca²⁺ in the regulation of tumor cell proliferation by products of arachidonic acid (AA) metabolism was investigated using U-373 MG human astrocytoma cells. Treatment with nordihydroguaiaretic acid (NDGA), a lipoxygenase (LOX) inhibitor, or caffeic acid (CA), a specific 5-LOX inhibitor, suppressed proliferation of the tumor cells in a dose-dependent manner. However, indomethacin (Indo), a cyclooxygenase (COX) inhibitor, did not significantly alter proliferation of the tumor cells. At anti-proliferative concentrations, NDGA and CA significantly inhibited intracellular Ca²⁺ release induced by carbachol, a known intracellular Ca²⁺ agonist in the tumor cells. Exogenous administration of leukotriene B₄ (LTB₄), an AA metabolite of LOX pathway, enhanced proliferation of the tumor cells in a concentration-dependent fashion. In addition, LTB₄ induced intracellular Ca²⁺ release. Intracellular Ca²⁺ inhibitors, such as an intracellular Ca²⁺ chelator (BAPTA) and intracellular Ca²⁺-release inhibitors (dantrolene and TMB-8), significantly blocked the LTB₄-induced enhancement of cell proliferation and intracellular Ca²⁺ release. These results suggest that LOX activity may be critical for cell proliferation of the human astrocytoma cells and that intracellular Ca²⁺ may play a major role in the mechanism of action of LOX.     

Modulation of mediator release from human basophils and pulmonary mast cells and macrophages by auranofin

Auranofin, a new orally absorbable gold compound, inhibits IgE-(anti-IgE) and non-IgE-mediated (f-met-peptide and the Ca2+ ionophore A23187) histamine release from human basophils. Auranofin inhibits the release of histamine induced by phorbol myristate (TPA) and bryostatin 1 both in the presence and absence of extracellular Ca2+. Increasing the Ca2+ concentrations in the extracellular medium does not reduce the inhibitory effect of auranofin on anti-IgE- or A23187-induced secretion. Auranofin inhibits the de novo synthesis of sulfidopeptide leukotriene C4 (LTC4) induced by anti-IgE from basophils and mast cells purified from human lung. However, in both systems auranofin has a significantly greater inhibitory effect on LTC4 release than on histamine secretion. Finally, auranofin induces a concentration-dependent inhibition of A23187-induced leukotrine B4 (LTB4) release from purified human lung macrophages. These data suggest that auranofin modulates the release of preformed (histamine) and de novo synthesized (LTC4 and LTB4) chemical mediators from human inflammatory cells isolated from peripheral blood and human lung tissues.     

Effect of a Chymotrypsin-like Inhibitor,TPCK, on Histamine Release from Cultured Human Mast Cells

The involvement of endogenous proteases in the secretory process from human mast cells remains to be clarified. A chymotrypsin-like protease inhibitor, N-tosyl-l-phenylalanylchloromethyl ketone (TPCK), blocked both FcεRI- and A23187-mediated histamine release from cultured human mast cells at concentrations above 1 μm. At 10 μm, the concentration that completely inhibited FcεI-mediated histamine release, TPCK did not inhibit the chymase activity of the lysate or that in intact cells. The addition of TPCK to cells 30 min before challenge did not affect FcεRI- or A23187-mediated Ca²⁺ mobilization. These findings suggest that a TPCK-sensitive molecule distinct from chymase is involved in a late stage of the process of histamine release from mast cells in man.     

Inhibitory effect of anti-allergic agent NCO-650 on histamine release induced by various secretagogues

Histamine release from rat peritoneal mast cells induced by antigen and anti-IgE was essentially complete within 2 min and 3 min, respectively, but that due to Concanavalin A (Con A) was complete only within 9 min. An anti-allergic agent NCO-650 [trans-4-Guanidinomethylcyclohexanecarboxylic acid p-tert-butylphenyl ester hydrochloride], which is a strong inhibitor of trypsin, dose-dependently inhibited anti-IgE-induced histamine release from rat peritoneal mast cells. Moreover, the rate and extent of histamine release from rat peritoneal mast cells induced by various histamine liberators such as antigen, concanavalin A, ionophore A 23187 and compound 48/80 are significantly diminished in samples incubated with NCO-650. The IC50 values of NCO-650 on histamine release induced by antigen, anti-IgE, Concanavalin A, A23187 and compound 48/80 were in the order of micromolar range, i.e. 1.9, 3.6, 4.6, 2.9 and 6.1 microM, respectively. On a molecular basis, NCO-650 is 1000-fold more potent than DSCG, an anti-allergic drug, in inhibiting the antigen-induced histamine release. The present results suggest that the effect of NCO-650 might be due to the inhibition of a common process underlying the release of histamine by various histamine liberators.