Effects of acute combined exposure to N-butyl alcohol and M-xylene.

The effects of combined exposure to m-xylene and n-butyl alcohol on rotarod performance and motor activity in rats and respiratory rate in mice were investigated in the condition of an acute inhalation experiment. Rotarod performance and motor activity were tested in rats exposed to various concentrations of m-xylene, n-butyl alcohol and their mixture consisting of 50 Vol-% m-xylene and 50 Vol-% n-butyl alcohol immediately after termination of a 4-hour exposure period. The respiratory rate in mice was recorded in short 6 min duration exposures to individual solvents and their 50:50 Vol-% mixture. Both solvents and mixtures caused concentration-dependent disturbances of rotarod performance in rats. The medial effective concentration (EC50) for the effect amounted 6530 ppm, 1980 ppm and 3080 ppm for n-butyl alcohol, m-xylene and their mixture, respectively. Both solvents and their mixture changed the spontaneous motor activity in the rat. Because of a two-phase effect, the concentration-dependence of the observed changes could not be defined. The evaluation of the combined effect in motor activity test was carried out by comparing experimental values with expected ones assuming the summation of individual solvent effects. The tested solvents resulted in a concentration-dependent decrease in respiratory rate in mice. The concentration which decreased the respiratory rate to 50% (RD50) was 3010 ppm, 1360 ppm and 3140 ppm for n-butyl alcohol, m-xylene and their mixture, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)