Effect of inhalation anaesthetics on division of bone-marrow cells in vitro

The effect of halothane or nitrous oxide or both, on division of cultured, murine bone-marrow cells was investigated. Halothane caused a dose-dependent depression of growth rate ranging from a minimal effect at 0.5% to almost total inhibition at 2.0%. Nitrous oxide 75% had an effect similar to 0.5% halothane and the combination of 0.75% halothane with 75% nitrous oxide produced results little different from 1.0% halothane alone. There was good recovery from 1.0% but not from 2.0% halothane. It is concluded that, in vitro, bone-marrow cells show a similar sensitivity to these agents as was found for other mammalian cell lines which have been investigated. The effect of nitrous oxide was no more than proportional to its narcotic potency relative to halothane.