Umezu T, Suzuki A K, Miura T, Koizumi A
Regional Environment Division, National Institute for Environmental Studies, Ibaraki, Japan.
Environ Res. 1993 Apr;61(1):51-67. doi: 10.1006/enrs.1993.1049.
Male ICR mice were exposed continuously to ozone (O3) and nitrogen dioxide (NO2) for 7 days to examine the effects on drinking and eating behaviors. Ozone at 0.1 ppm did not affect drinking and eating activities, whereas drinking activity decreased in a concentration-dependent manner to 47.7, 12.8, and 3.0% of the control value with 2-day exposures to 0.2, 0.4, and 0.8 ppm O3, respectively, and eating activity decreased to 35.2 and 8.7% of the control value at 0.4 and 0.8 ppm O3, respectively. Body weight also decreased markedly by 2.0, 4.6, and 7.5 g at 0.2, 0.4, and 0.8 ppm O3, respectively. These decrements reached a maximum on the second day of exposure. However, alterations in drinking and eating activities and body weight were transient, leading to recovery during the continuous O3 exposures. The recovery processes were dependent on the concentrations of O3. Nitrogen dioxide at 4 ppm did not affect drinking and eating activities, whereas drinking activity decreased in a concentration-dependent manner to 56.8, 8.3, and 18.7% of the control value with 2-day exposures to 6, 8, and 12 ppm NO2, respectively, and eating activity decreased markedly to 21.8 and 16.4% at 8 and 12 ppm NO2, respectively. Body weight also decreased by 2.5, 5.5, and 6.1 g at 6, 8, and 12 ppm NO2, respectively. These decrements reached a maximum on the second day of exposure. As in the O3 exposures, the decrements in drinking and eating activities and body weight were transient and recovered during the continuous exposures to NO2 depending on the concentrations of NO2. Drinking and eating activities and body weights of mice that had been previously exposed to 12 ppm NO2 for 7 days did not show changes when the mice were exposed to 0.4 ppm O3 9 days after NO2 exposure. The present study demonstrates that photochemical oxidants suppress drinking and eating behaviors in mice and that they recover thereafter under the continuous exposure conditions.
将雄性ICR小鼠连续暴露于臭氧（O3）和二氧化氮（NO2）中7天，以研究其对饮水和进食行为的影响。0.1 ppm的臭氧不影响饮水和进食活动，而分别连续2天暴露于0.2、0.4和0.8 ppm O3时，饮水活动以浓度依赖的方式下降至对照值的47.7%、12.8%和3.0%，进食活动在0.4和0.8 ppm O3时分别下降至对照值的35.2%和8.7%。在0.2、0.4和0.8 ppm O3时，体重也分别显著下降2.0、4.6和7.5 g。这些下降在暴露的第二天达到最大值。然而，饮水和进食活动以及体重的变化是短暂的，在持续暴露于臭氧期间会恢复。恢复过程取决于臭氧的浓度。4 ppm的二氧化氮不影响饮水和进食活动，而分别连续2天暴露于6、8和12 ppm NO2时，饮水活动以浓度依赖的方式下降至对照值的56.8%、8.3%和18.7%，进食活动在8和12 ppm NO2时分别显著下降至21.8%和16.4%。在6、8和12 ppm NO2时，体重也分别下降2.5、5.5和6.1 g。这些下降在暴露的第二天达到最大值。与暴露于臭氧的情况一样，饮水和进食活动以及体重的下降是短暂的，在持续暴露于二氧化氮期间会根据二氧化氮的浓度恢复。先前连续7天暴露于12 ppm NO2的小鼠，在二氧化氮暴露9天后暴露于0.4 ppm O3时，其饮水、进食活动和体重没有变化。本研究表明，光化学氧化剂会抑制小鼠的饮水和进食行为，并且在持续暴露条件下它们随后会恢复。
