Toxic effects of acute inhalation exposure to 1,2,4,5-tetramethylbenzene (durene) in experimental animals.

Neurotoxic and sensory respiratory irritation effects of 1,2,4,5-tetramethylbenzene (durene) in male rats and male Balb/C mice were investigated in the condition of acute inhalation exposure. Rotarod performance and pain sensitivity behaviour were tested in rats exposed to durene at concentrations of 880, 1100 and 1280 mg/m3 immediately after termination of a four-hour exposure. The respiratory rate was measured in mice by the whole body pletysmographic method in a 6-min exposure to various concentrations of durene. Exposure to durene resulted in concentration-dependent decrease in pain sensitivity in rats and depression of respiratory rate in mice. At applied durene concentrations, no statistically significant disturbances in rotarod performance behaviour were observed. The concentration depressing the respiratory rate to 50% (RD50) was 838 mg/m3. As based on RD50 value, MAC of 25 mg/m3 is suggested for durene.