Effects of infrasound at 8 Hz 90 dB/130 dB on NMDAR1 expression and changes in intracellular calcium ion concentration in the hippocampus of rats.

In the present study, we investigated the effect of infrasound on the expression of N-methyl-D-aspartate (NMDAR)1 as well as changes in intracellular calcium ion concentration ([Ca2+]i) in the hippocampus of rats. Sprague-Dawley (SD) rats were exposed for 2 h daily to infrasound at 8 Hz 90 dB or 130 dB, and NMDAR1 expression was examined on days 1, 7, 14, 21 and 28. The expression of NMDAR1 in the rat hippocampus upon exposure to infrasound at 8 Hz 90 dB sound pressure level (SPL) showed an initial decrease on day 1, an increase on days 7 and 14, a further decrease on day 21, and a return to normal levels on day 28.

[Observation of the L929 cell membrane after infrasound exposure with atomic force microscope].

Objective: To observe the changes of L929 cell membrane with atomic force microscope (AFM) after infrasound exposure and to explore the mechanisms of effect of infrasound on cell membrane.

Methods: After primary culture, the L929 cells were exposed to infrasound with intensity output of 130 dB and frequency of 16 Hz 2 hours each day for 3 days. The subsequent changes in the membrane of the control cells and the cells exposed to the infrasound were determined by nano-scale scanning with AFM.

[Effects of infrasound exposure on several enzymes activities of spleen and liver in rats].

Aim: To investigate the changes of several enzymes activities in the spleen and liver of rats after exposure to 8 Hz 130 dB infrasound for different time.

Methods: Thirty-five male SD rats were randomly divided into five groups. Rats of group 1 served as control, rats from group 2 to 5 were exposed to 8 Hz 130 dB infrasound, 2 hours per day, for 1 wk, 2 wk, 3 wk, and 4 wk, respectively.

[Effects of infrasound on visual electrophysiology in mice].

Objective: To investigate the possible effects of infrasound on visual functions.

Method: One hundred and fifty mature male Kunming-mice were divided into 5 groups, in which one was control and the other four were exposed to infrasound of 8 Hz, 90 dB; 8 Hz, 130 dB; 16 Hz, 90 dB and 16 Hz, 130 dB 2 h/d respectively. The exposure time for them were 0, 1, 4, 7, 14 and 21 d respectively, each group was divided into 6 sub-groups.

[Effects of infrasound on ultrastructure of testis cell in mice].

Objectives: To investigate the effects of infrasound on ultrastructure of testis in mouse.

Methods: Twelve male BALB/C mice were randomly divided into three groups according to exposed duration on 1, 7 and 14 day. The mice were separately exposed to infrasound environment under 8 Hz/90 dB, 8 Hz/130 dB, 16 Hz/90 dB, 16 Hz/130 dB 2 hours per day.