Behavioral Toxicology of Volatile Organic Solvents. IV. Comparisons of the Rate-Decreasing Effects of Acetone, Ethyl Acetate, Methyl Ethyl Ketone, Toluene, and Carbon Disulfide on Schedule-Controlled Behavior of Mice

The effects of acetone (ACE), ethyl acetate (EAC), methyl ethyl ketone (MEK), toluene (TOL), and carbon disulfide (CS2) were compared on schedule-controlled responding of mice. Responding (the interruption of a photocell beam located behind a nose-poke hole) was maintained under a fixed interval (FI) 60-second schedule of milk presentation in a sealed inhalation chamber. Cumulative concentration-effect functions were obtained by increasing the concentration of each solvent within the chamber, at 30-minute intervals until responding was abolished. Responding was assessed again 30 minutes after the termination of exposures to levels that abolished responding, to assess the extent of recovery. TOL, CS2, and ACE slightly increased rates of responding at lower concentrations. Each solvent decreased responding in a concentration-related manner at higher concentrations, with responding being decreased 50% by 10,694 ppm ACE, 594 ppm EAC, 2891 ppm MEK, 1784 ppm TOL, and 2242 ppm CS2. Responding recovered 30 minutes after exposures completely for ACE, EAC, and MEK, approximately 75% for TOL, but not at all for CS2. These data suggest that the acute behavioral toxicity of EAC, relative to that found for the other solvents, may be greater than that reflected in current threshold limit values (TLV).