An inhalation method for testing the toxicity of volatile compounds in small laboratory animals. A study on short-term and long-term toluene inhalation in rats.

A coupola-shaped Plexiglass inhalation chamber (volume 190 I) with continuous infusion of toxicant and air flow was constructed for small laboratory animals. The method guarantees an even distribution of vapourized toxicant to 16 animals at the same time, and is convenient both in short-term and long-term experiments. As a volatile toxicant, toluene was used. The short-term and long-term effects of toluence on rats were studied using psychomotor tests, blood glucose, serum ALAT and ASAT values as well as hematocrit. Short-term exposure, but not long-term, impaired the performance in psychomotor tests, elevated blood glucose and serum ALAT and ASAT levels, and slightly increased hematocrit. Body weight decreased as compared to controls in short-term toluene exposure, but showed no difference in long-term treatment between toluene-and control groups at the end of exposure. The differences between the two exposures are probably due to the development of tolerance during long-term exposure either on receptor or metabolic level.