The effect of U50488, a selective K-opioid receptor agonist, on cardiac rhythm in the isolated perfused rat heart and intracellular calcium ([Ca2+] i) in the single ventricular myocyte were studied. The results showed...The effect of U50488, a selective K-opioid receptor agonist, on cardiac rhythm in the isolated perfused rat heart and intracellular calcium ([Ca2+] i) in the single ventricular myocyte were studied. The results showed that U50488 can induce arrhythmias dose-dependently in the isolated perfused rat heart and increase [ Ca2 + ] i in the single ventricular myocyte. The effect of U50488 can be blocked by a selectivek-receptor antagonist, nor-binaltorphimine. The arrhythmogenic effects and the increase of [ Ca2+]i induced by U50488 were blocked by U73122, neomycin and streptomycin, which are selective phospolipase C inhibitors, but not by U73433, the inactive structural analog of U73122. These results demonstrated that the arrhythmogenic effect of cardiac K-receptor is due to activation of phosphoinositol/Ca2+ pathway.展开更多
To study the effects of 18β-glycyrrhetinic acid (GA) on proliferation inhibition, apoptotic induction, and the relationship between GA-induced apoptosis and intracellular Ca^2+ concentration in human breast carcinoma...To study the effects of 18β-glycyrrhetinic acid (GA) on proliferation inhibition, apoptotic induction, and the relationship between GA-induced apoptosis and intracellular Ca^2+ concentration in human breast carcinoma (MCF-7) cells. Methods: After MCF-7 cells were treated with GA at the concentrations from 50 μmol/L to 250 μmol/L for 24 h, cell viability of proliferation was as sessed by MTTassay. After the cells were treated with 100 μmol/L, 150 μmol/L, and 200 μmol/L GA for 24 h, the rates of cell apoptosis were examined by terminal deoxynucleotide transferase mediated dUTP nick-end-labeling method and flow cytometry with Annexin V/propidium iodide fluorescent stain. After the cells treated with 150 μmol/L GA for 24 h, intracellular Ca^2+ concentration was measured by Fure-2 fluorescein load method. Results: After the cells were treated with GA at the concentrations from 100 μmol/L to 250 μmol/L, the rates of proliferative inhibition were increased significantly (P<0.05 and P<0.01) in a dosedependent fashion. IC50 of the proliferation inhibition was 234.33 μmol/L. Treated with 100 μmol/L, 150 μmol/L, and 200 μmol/L, the rates of cell apoptosis were increased significantly (P<0.01). Intracellular Ca^2+ concentration after treatment with GA was higher evidently than that of control (P<0.05). Conclusion: 18β-glycyrrhetinic acid has the effects of the proliferation inhibition and the apoptotic induction on MCF-7 cells. The rise of intracellular Ca^2+ level may be depended on apoptosis induced by GA in MCF-7 cells.展开更多
Abstract Objective:To explore the effects of γ-irradiation on mitogen-activatedprotein kinases(MAPKs) and role intracellular calcium in this event in intestinal epithelial cell line 6(IEC-6 cells).Methods:After cultu...Abstract Objective:To explore the effects of γ-irradiation on mitogen-activatedprotein kinases(MAPKs) and role intracellular calcium in this event in intestinal epithelial cell line 6(IEC-6 cells).Methods:After cultured rat IIEC-6 cells with or without the pretreatment of intracellular Ca^2+ chelator were exposed to γ-ir-radiation of 6 Gy, the total and phosphorylated MAPKs in the cells were determined with Western blotting and apoptosis was examined with flow cytometry.Activities of Extracellular signal-regulated protein kinase (ERK) and p38 MAPK were determined by using immuoprecipitation followed by Western blotting.Results:In response to γ-irradiation,phosphorylation of ERK was not significantly observed ,while the levels of phos-phorylated c-Jun NH2-terminal kinase(JNK) and p38 MAPK were increased in 30 min and reached the peak 2h after exposure to 6Gy γ-irradiation,though the cell viability was significantly lowered 12h.On the other hand, no obvious changes were seen in the total protein levels of ERK, JNK and p38 MAPK.Chelation of in-tracellular Ca^2+ almost completely suppressed the JNK and p38 MAPK phosphorylation induced by γ-irradiation is a potent activator for JNK and p38 MAPK, and Ca^2+ mobilized from intracellular stores plays an important role in the activation of MAPKs and the induction of apoptosis in IEC-6 cells.展开更多
文摘The effect of U50488, a selective K-opioid receptor agonist, on cardiac rhythm in the isolated perfused rat heart and intracellular calcium ([Ca2+] i) in the single ventricular myocyte were studied. The results showed that U50488 can induce arrhythmias dose-dependently in the isolated perfused rat heart and increase [ Ca2 + ] i in the single ventricular myocyte. The effect of U50488 can be blocked by a selectivek-receptor antagonist, nor-binaltorphimine. The arrhythmogenic effects and the increase of [ Ca2+]i induced by U50488 were blocked by U73122, neomycin and streptomycin, which are selective phospolipase C inhibitors, but not by U73433, the inactive structural analog of U73122. These results demonstrated that the arrhythmogenic effect of cardiac K-receptor is due to activation of phosphoinositol/Ca2+ pathway.
文摘To study the effects of 18β-glycyrrhetinic acid (GA) on proliferation inhibition, apoptotic induction, and the relationship between GA-induced apoptosis and intracellular Ca^2+ concentration in human breast carcinoma (MCF-7) cells. Methods: After MCF-7 cells were treated with GA at the concentrations from 50 μmol/L to 250 μmol/L for 24 h, cell viability of proliferation was as sessed by MTTassay. After the cells were treated with 100 μmol/L, 150 μmol/L, and 200 μmol/L GA for 24 h, the rates of cell apoptosis were examined by terminal deoxynucleotide transferase mediated dUTP nick-end-labeling method and flow cytometry with Annexin V/propidium iodide fluorescent stain. After the cells treated with 150 μmol/L GA for 24 h, intracellular Ca^2+ concentration was measured by Fure-2 fluorescein load method. Results: After the cells were treated with GA at the concentrations from 100 μmol/L to 250 μmol/L, the rates of proliferative inhibition were increased significantly (P<0.05 and P<0.01) in a dosedependent fashion. IC50 of the proliferation inhibition was 234.33 μmol/L. Treated with 100 μmol/L, 150 μmol/L, and 200 μmol/L, the rates of cell apoptosis were increased significantly (P<0.01). Intracellular Ca^2+ concentration after treatment with GA was higher evidently than that of control (P<0.05). Conclusion: 18β-glycyrrhetinic acid has the effects of the proliferation inhibition and the apoptotic induction on MCF-7 cells. The rise of intracellular Ca^2+ level may be depended on apoptosis induced by GA in MCF-7 cells.
基金in part by Natural Sciences Foundation of China (No. 39870239)by the Sasagawa Fellowship,Japan.
文摘Abstract Objective:To explore the effects of γ-irradiation on mitogen-activatedprotein kinases(MAPKs) and role intracellular calcium in this event in intestinal epithelial cell line 6(IEC-6 cells).Methods:After cultured rat IIEC-6 cells with or without the pretreatment of intracellular Ca^2+ chelator were exposed to γ-ir-radiation of 6 Gy, the total and phosphorylated MAPKs in the cells were determined with Western blotting and apoptosis was examined with flow cytometry.Activities of Extracellular signal-regulated protein kinase (ERK) and p38 MAPK were determined by using immuoprecipitation followed by Western blotting.Results:In response to γ-irradiation,phosphorylation of ERK was not significantly observed ,while the levels of phos-phorylated c-Jun NH2-terminal kinase(JNK) and p38 MAPK were increased in 30 min and reached the peak 2h after exposure to 6Gy γ-irradiation,though the cell viability was significantly lowered 12h.On the other hand, no obvious changes were seen in the total protein levels of ERK, JNK and p38 MAPK.Chelation of in-tracellular Ca^2+ almost completely suppressed the JNK and p38 MAPK phosphorylation induced by γ-irradiation is a potent activator for JNK and p38 MAPK, and Ca^2+ mobilized from intracellular stores plays an important role in the activation of MAPKs and the induction of apoptosis in IEC-6 cells.
