Effects of 1,1,1-trichloroethane administered by different routes and in different solvents on barbiturate hypnosis and metabolism in mice.

A 24-hr inhalation of 1,1,1-tricholoroethane (methylchloroform), 3,000 ppm, reduced pentobarbital hypnosis and increased hexobarbitaloxidation by the 9,000 x g liver supernatant fraction in male mice. On the other hand, an ip injection of methylchloroform, l ml/kg, increased the duration of pentobarbital hypnosis and reduced hexobarbital metabolism by the liver microsomal enzymes. The potentioating effect of methylchloroform on pentobarbital hypnosis as diminished when it was diluted with olive oil, but was markedly enhanced when diluted with dimethysusoxide (DMSO) before injection. Three local applications of methylchloroform )1:1 dilution with DMSO) had an effect similar to that of inhalation on pentobarbital hypnosis.