Calcium caused calcium release causes a vascular smooth muscle cell line A10 cells apoptosis / 中国临床药理学与治疗学

ABSTRACT

AIM: To investigate the apoptosis of a vascular smooth muscle cell line A10 caused by mild K+ depolarization. METHODS: Apoptosis was evaluated by nuclear staining, DNA fragmentation gel electrophoresis and propidium iodide-stained flow cytometry. Mitochondrial transmembrane potential (Δψm) was measured by flow cytometry. RESULTS: K+ depolarization caused dose correlated A10 cells apoptosis; nifedipine, BAPTA/AM, ryanodine inhibited the cytotoxic effect of K+ completely.The combination use of nifedipine and cyclosporin A made it clear that mitochondria was involved in the apoptosis of A10 cells,and Δψm measurement further confirmed this speculation; A10 apoptosis caused by K+ depolarization was not influenced by heparin or Zn2+,a effective capacitative calcium entry(CCE) blocker. CONCLUSION: Ca2+ entry through voltage-dependent ca channels increases intracytoplasm Ca2+, then triggers further Ca2+ release from endoplasmic reticulum via ryanodine receptor, and the microdomains of elevated intracytoplasm Ca2+ are sensed by adjacent mitochondria, which ultimately lead to cell apoptosis.