[Frequency of chromosome aberrations induced by stress and cyclophosphane in bone marrow cells of rats selected for the threshold of nervous system excitability].

The frequency of chromosomal aberrations in bone marrow cells under the effect of long-term stress and cyclophosphamide was studied in rat lines selected for different levels of nervous system excitability. After both kinds of treatment, differences between lines in frequencies of chromosomal aberrations were observed. Stress had a weak mutagenic effect on rats with a low level of excitability, but no such effect on highly excitable rats. Correlations between cytogenetic parameters of chromosomal aberrations induced by cyclophosphamide and the functional state of the nervous system were ambiguous. Thus, the frequency of single and paired chromosome fragments did not show any apparent correlation with the excitability of animals. The frequency of translocation-like chromosomal interchanges in highly excitable rats was higher than in weakly excitable rats. In terms of the number of cells with aberrations, a dependence of the type of interlinear differences on the selection program was observed. Possible mechanisms responsible for differences in susceptibility of animals to the action of mutagenic factors are discussed in relation to peculiarities of the functional state of the nervous system in the studied lines.