Behavioral and plasma monoamine responses to high-speed railway noise stress in mice.

Studies have reported that railway noise causes stress responses. To evaluate the effects of high-speed railway (HSR) noise on behaviors and plasma monoamines. Institute of cancer research mice were exposed to previously recorded HSR noise for 53 days. The noise was arranged according to the HSR's 24-h traffic number and adjusted to a day-night equivalent continuous A-weighted sound pressure level (Ldn ) of 70 dB (A). The open field test (OFT) and the light/dark box test were applied to observe mice behaviors. High performance liquid chromatography-fluorimetric detection was performed to determine the concentrations of plasma norepinephrine (NE), dopamine (DA), serotonin (5-hydroxytryptamine, 5-HT). Data were analyzed by two-way analysis of variance using SPSS 16.0. After 53 days of noise exposure, center time and the frequency of line crossing of the exposed mice decreased significantly in the OFT compared with the control group. Meanwhile, transitions and the time spent in the lit compartment of the exposed group decreased significantly in the light/dark box test. After 40 days of HSR noise exposure, the concentrations of plasma DA of the exposed group were significantly higher than those of the control group, while the plasma NE and 5-HT concentrations showed no significant difference between the two groups. The behavioral tests indicate that 70 dB (A) HSR noise can result in anxiety-like behaviors in mice. The physiological results show that plasma DA is more sensitive to HSR noise compared with NE and 5-HT.