The effect of methyl n-butyl ketone on response rates of rats performing on a multiple schedule of reinforcement

Six rats were tested daily on a multiple fixed ratio 5 fixed interval 3-minute schedule of reinforcement. Saline (control) oral administrations were given during each week of testing except for 1 day per week on which methyl n-butyl ketone (MBK), an industrial solvent, was administered orally in concentrations of 68, 135, 270, or 406 mg/kg (representing 3, 5, 10, and 16%, respectively, of the oral LD₅₀). Each rat received each MBK concentration on three to six occasions over the course of the study. When compared to the preceding control (saline) day, fixed interval performance (response rate) after MBK administration was reduced by a mean of 20% at 68 mg/kg, 30% at 135 mg/kg, 40% at 270 mg/kg, and 57% at 406 mg/kg. All changes were statistically significant at P ≤ 0.03.