丙二醛破坏大鼠海马神经元胞质钙离子稳态的信号机制

目的研究丙二醛（MDA）对原代培养的海马神经元胞质中钙离子稳态的破坏作用及可能的信号机制。方法以Fur2／AM为荧光指示剂，采用荧光分光光度法定量测定原代培养海马神经元胞质游离钙浓度变化。结果随着MDA浓度的升高和作用时间的延长，导致胞质中游离钙水平显著升高，破坏其钙稳态。MDA所导致的海马神经元胞质游离钙水平升高包括两个过程：100μmol／L的MDA可使胞质Ca2＋]i水平在0—10min内的早期渐进升高过程，经历中间大约5min的平台期后，接下来15—30min的晚期显著升高。以细胞膜电压依赖的Ca2＋通道抑制剂nimodipine抑制外钙内流后，可显著抑制晚期胞质Ca2＋]i水平的升高，以PLC的抑制剂U73122作用后，则可抑制早期胞质Ca2＋]i水平的升高。结论100μmol／L的MDA作用下，海马神经元胞质中早期钙离子水平的升高和晚期钙离子水平的升高可能分别由不同的信号机制所介导。

Signaling mechanisms of calcium homeostasis disruption induced by malondialdehyde in primary cultured rat hippocampal neurons

Objectivie To investigate the effect of malondialdehyde on the calcium homeostasis disruption in primary cultured rat hippocampal neurons, their possible mechanisms and signaling pathways of to the effects. Methods The concentration of cytosolic free calcium （ Ca2＋ ]i） was determined by fluorescence speetrophotometry with Fur2/AM as an indicator. Results The levels of Ca2＋]i were increased with the increasing MDA concentrations in the primary cultured hippocampal neurons and the duration of time, and the calcium homeostasis was disturbed. The increase of Ca2＋]i induced by 100μmol/L MDA showed two stages. The early stage was from 0 -10 min, and the late stage was from 15 -30 min. The increase of Ca2＋]i in the early stage was inhibited by U73122, a PLC inhibitor, indicating that this increase of Ca2＋]i may be induced by the PLC/IP3 signaling pathway. The increase of Ca2＋]i in the late stage was inhibited by nimodipine, a calcium channel antagonist, indicating that the increase of Ca2＋]i in the late stage may be induced by the L- voltage operation calcium channel （ L-VOCC ） signal pathways. Conclusion The mechanisms of Ca2＋]i increase induced by 100 μmol/L MDA may involve two different signaling pathways.