Concentration-dependent behavioral changes in mice following short-term inhalation exposure to various industrial...

Mice were exposed during a 4-hr period to various concentrations of 13 aliphatic or aromatic solvents which affect primarily the central nervous system (CNS). The test compounds were benzyl chloride, butyl alcohol, chlorobenzene, cyclohexanone, 1,2-dichloroethylene, diisobutyl ketone, isopropyl acetate, methyl ethyl ketone, styrene, tetrachloroethylene, 1,1,1-trichloroethane, toluene, and ortho-xylene. After exposure, measurements were made to see whether these neurotoxicants would decrease the immobility developed in a "behavioral despair" swimming test. Each chemical was shown to reduce the total duration of immobility measured over a 3-min period in a concentration-related manner. The systematic determination of the atmospheric concentrations responsible for a 50% decrease in immobility (ID50) permitted classification of the solvents in terms of their relative potencies. The possibility of using such experimental data as tentative guidelines for setting safe levels of work exposure to the neurotoxicants was suggested, considering the existence of quantitative relationships between the ID50 values and the current occupational standards.