PTSD样情感行为异常大鼠海马ATP酶活性与Ca^(2+)/CaM改变

ATPase activities and Ca^(2+)/calmodulin alterations in hippocampi of rats with PTSD-like behaviors

目的 :探讨创伤后应激障碍 (PTSD)精神与行为异常的病理生理基础。方法 :通过频率 2 5Hz、波宽 1ms、串长 10s、串隔 7min、强度 10 0 μA的恒流、单向方波 ,建立海马惊厥阈下电刺激PTSD动物模型 ;采用神经生化、流式细胞仪、荧光标记术及Westernblotting等方法 ,定量观测了实验动物海马Na+ -K+ -ATP酶、Ca2 + -ATP酶活性 ,细胞内Ca2 + 含量与钙调素 (CaM)相对活性平均通道荧光及海马组织总CaM表达的动态变化规律。结果 :电刺激停止后 4 8h内实验动物海马细胞线粒体Na+ -K+ -ATP酶活性明显下降 ,72h内Ca2 + -ATP酶活性显著降低 ;海马细胞 [Ca2 + ]i于电刺激停止后 72h内明显增高 ,游离CaM平均通道荧光则同步降低 ,而海马组织总CaM表达则于电刺激停止后 4 8h内明显增多。结论 :海马细胞 [Ca2 + ]i持续增高、结合CaM含量明显增加及线粒体钠钾泵与钙泵功能受损 ,可能是实验动物长时程PTSD样情感行为异常的重要病理生理基础之一。

AIM: To explore the pathophysiological bases in the pathogenesis of the lasting emotional behavioral disorders following posttraumatic stress disorder (PTSD). METHODS: 240 male Wistar rats were divided randomly into 3 groups. Group SE ( n =96) for rats with PTSD-like behavior by constant pulsating current of 100 μA with intratrain frequencies of 16 Hz, pulsating duration of 1 ms, train duration of 10 s and interstimulus interval of 7 min for 5 days with 8 times per day. Group CE ( n =96) for control with electrode implanted in hippocampus without stimulation, and Group NC ( n =48) for normal control. The activities of Na +-K +-ATPase and Ca 2+ -ATPase, levels of intracellular calcium and free calmodulin (CaM), and the total CaM expression were detected in hippocampi of experimental rats. RESULTS: The activities of Na +-K +-ATPase and Ca 2+ -ATPase in mitochondria of hippocampal cells in Group SE rats were significantly decreased at 48 h and 72 h after the last stimulation, respectively. The intracellular free calcium levels were increased, and the mean channel fluorescence of intracellular free CaM decreased remarkably at 72 h poststimulation, while the expression of total CaM was significantly elevated at 48 h after the last stimulation in hippocampi of Group SE rats. CONCLUSION: The lasting increased levels of intracellular free calcium and expression of Ca 2+ -CaM in hippocampus, as well as the dysfunction of Na +-K + pump and Ca 2+ -ATPase in mitochondria may play important roles in the long-term neuropsychological sequelae in PTSD.