PTSD样情感行为异常大鼠海马ATP酶活性与Ca2+/CaM改变

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25Hz、波宽1ms、串长10s、串隔7min、强度100μA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48h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48h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。

ATPase activities and Ca2+/calmodulin alterations in hippocampi of rats with PTSD-like behaviors

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 Ca²⁺ -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 Ca²⁺ -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 Ca²⁺ -CaM in hippocampus, as well as the dysfunction of Na⁺-K⁺ pump and Ca²⁺ -ATPase in mitochondria may play important roles in the long-term neuropsychological sequelae in PTSD.