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[Inhibition of 5 calcium channel blockers on H2O2 release from mouse peritoneal macrophages]
Abstract:
After the peritoneal macrophages from mice were incubated with different concentrations of calcium channel blockers for 3 h at 37 degrees C, the macrophages were stimulated with opsonized zymosan for 1.5 h at 37 degrees C. The released H2O2 was measured by fluorescence assay. The results showed that verapamil (Ver), nifedipine (Nif), nicardipine (Nic), nimodipine (Nim), and nitrendipine (Nit) reduced the H2O2 release significantly in a dose-dependent manner. The IC50 values (mumol.L-1) were 30, 50, 49, 63, and 92 for Nic, Nif, Nim, Nit, and Ver, respectively. There was slight inhibition of dihydropyridine (Bay k 8644) 10 mumol.L-1 on H2O2 release. When Bay k 8644 at above concentration combined with Ver, Nim, and Nit 25 mumol.L-1, respectively, the inhibitions of Ver, Nim, and Nit on H2O2 release were increased 32%-40%. Above results showed that on the inhibition of H2O2 release, the effects of dihydropyridines calcium channel blockers were greater than that of Ver, and the effects of Nic and Nif were greater than those of Nim and Nit. The acting sitei of Bay k 8644 at high concentration (10 mumol.L-1 and over) was probably different from that of typical calcium channel blockers Nim, Nit, and Ver in macrophages.
Insights
Calcium channel blockers like nicardipine and nifedipine significantly reduced hydrogen peroxide (H2O2) release from macrophages. Dihydropyridines showed greater inhibitory effects, suggesting distinct mechanisms of action.
Area of Science:
- Immunology
- Pharmacology
Context:
- Macrophages play a crucial role in the immune response, releasing hydrogen peroxide (H2O2) during phagocytosis.
- Calcium channels are critical for regulating cellular functions, including macrophage activation.
Purpose:
- To investigate the inhibitory effects of various calcium channel blockers on H2O2 release from mouse peritoneal macrophages.
- To compare the efficacy of different calcium channel blockers and explore potential synergistic effects with Bay k 8644.
Summary:
- Verapamil, nifedipine, nicardipine, nimodipine, and nitrendipine dose-dependently inhibited H2O2 release.
- Dihydropyridine calcium channel blockers demonstrated greater inhibitory potential than verapamil.
- Nicardipine and nifedipine exhibited stronger inhibition compared to nimodipine and nitrendipine.
Impact:
- Identifies specific calcium channel blockers with potent H2O2 release inhibitory properties in macrophages.
- Suggests that dihydropyridines may act through different mechanisms than verapamil at high concentrations.
- Provides insights into the pharmacological modulation of macrophage inflammatory responses.