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    Effects of infrasound with 8 Hz, 130 dB on accumulation of Ca2+ in hippocampal cells of rat brain

    LIU Zhaoª²Hui, CHEN Jingª²Zao, WANG Zhiª²Peng, CHEN Dan, LI Jing, JIN Cheng

    1Department of Radiation Medicine, School of Preventive Medicine, 2Department of Pharmacology, 3Department of Electron Microscope, School of Basic Medicine, Fourth Military Medical University Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To study the effects of infrasound on Ca2+ in hippocampal cells. METHODS: Fortyª²eight SD rats were randomized into 6 groups: Control group, 1 d infrasound exposed group, 7 d infrasound exposed group, 14 d infrasound exposed group, 21 d infrasound exposed group and 28 d infrasound exposed group. Infrasound exposed groups were put to a field with 8 Hz, 130 dB infrasound, each day for 2 h. Acute cell separation technique, fluoª²3/AM fluorescence technique and laser scanning confocal microscope were used to measure the intracellular calcium level in hippocampus. RESULTS: Compared with control group, increase of intracellular calcium ion was recorded in the 1 d infrasound exposed group (P<0.01) and continuous increase was also recorded in the 7 d infrasound exposed group. The peak level and intracellular calcium ion overloaded were recorded in 14 d exposed group but the intracellular calcium ion restored to normal in 28 d exposed group. CONCLUSION: The exposure of 8 Hz, 130 dB infrasound for different periods can induce intracellular Ca2+ increases of different degrees. There is an adaptation in hippocampal cells with the lengthening of infrasound exposure time. ......