EFFECTS OF ACUTE AND CONTINUOUS OZONE (O-3) EXPOSURE ON ACTIVITY EXPLORATION AND SOCIAL-BEHAVIOR OF CD-1 MICE/

This study was aimed at investigating the behavioral effects of ozone (O-3) exposure in CD-1 mice. Pairs of same-sex adult male and female m ice were continuously exposed for 13 days to either 0, 0.4, 0.8, or 1. 2 ppm O-3. The exposure apparatus consisted of a system for O-3 produc tion and delivery into four stainless-steel chambers, each equipped to contain up to 24 home cages, with continuous monitoring and recording of concentrations. Acute behavioral changes were assessed during the first hour of O-3 exposure without removing animals from the chambers. The onset of exposure produced remarkable behavioral disturbances con sisting of a sharp in crease of several responses (rearing, sniffing, grooming, feeding and social interactions) paralleled by a reduction o f bar-holding. These changes were rapidly reversed within 1 hour, sugg esting that they constituted a response to strong novel stimulation fo llowed by habituation. Subsequently, brief sessions of videorecording of the animals' activities in freshly cleaned cages (identical to the home cages) were performed outside the chambers after 3, 7, and 10 day s of exposure. These tests showed a significant concentration-dependen t increase of grooming and rearing and a decrease of crossing and wall climbing. Both food and water intake showed a nonmonotonic trend over time consisting of a concentration-dependent depression (for about 3 and 7 days, respectively) followed by recovery; body weight followed a similar trend. The detailed study of various components of the animal 's behavioral repertoire, showing concentration-dependent and time-dep endent changes in different directions, appears to be a sensitive tool in the analysis of pollutants' effects. (C) 1994 Intox Press, Inc.