The effects of aircraft noise exposure on rat behavior and serum neurotransmitter expression

In order to investigate the physiological effects of airport noise exposure on organisms, in this study, we exposed Sprague-Dawley rats in soundproof chambers to previously recorded aircraft-related noise for 36 days. For comparison, we also used unexposed control rats. Noise was arranged according to aircraft flight schedules and was adjusted to its weighted equivalent continuous perceived noise level (L _WECPN) of 75 dB and 80 dB for the two experimental groups. We examined rat behavior through open field experiments and measured the concentrations of serum neurotransmitters (norepinephrine (NE) and 5-hydroxytryptamine (5-HT)) by high performance liquid chromatography-fluorimetric detection (HPLC-FLD). Our results showed that rats that were exposed to airport noise of 80 dB spent more time in the central part of the open field, the number of cross-lattices they crossed reduced significantly (P<0.05), and their frequency of grooming and defecation increased significantly (P<0.05), compared to control animals. The concentrations of serum NE of experimental groups were higher than that of the control group, and a dose-effect relationship was seen between NE concentration and the intensity of noise exposure. On the contrary, serum 5-HT concentrations of the experimental groups were always lower than that of the control group.