Development of Tolerance Against Ozone Effects on Drinking and Eating Behaviors in Rats by Intermittent Exposures

Abstract

AbstractThis study exammed the effects of intermittent exposures to 0.4–0.8 ppm ozone (O3) on drinking and eating behaviors in rats to evaluate the development of tolerance to O3 exposure. When rats were exposed to 0.4 ppm (787 μg/m3) O3 for 23 h the first time, the drinking activity was reduced to 29% of the control value and the eating activity to 44%. A decrease in body weight (mean decrease 11 g) was also noted. However, the magnitude of these changes was attenuated when the rats were exposed to 0.4 ppm O3 on day 2, 4, or 7 after the first exposure. When rats were exposed to 0.4 ppm O3 and then to 0.8 ppm (1577 μg/m3) O3 7 days later, the magnitude of decrease in the drinking activity was considerably smaller during the second exposure compared with that of a single exposure to 0.8 ppm O3. The lowered drinking activity by O3 exposure did not produce a postexposure compensatory increase of water intake. Moreover, deprivation of food and water prior to O3 exposure scarcely affected decrease in drinking ...