On the Action of Nitric Oxide on Radiation-sensitivity

Summary

The influence of nitric oxide (NO) on the radiation response of the bacteria E. coli and S. flexneri is studied. The results show that NO increases the sensitivity of the organism to radiation relative to the sensitivity in NO and that the degree of sensitization depends on the concentration of NO; pre-treatment with NO increases subsequent anoxic radiation sensitivity (pre-treatment effect); anaerobic-fermentation ability is decreased by pre-treatment with NO. The evidence suggests that the mechanism of action of NO is the same in the two organisms and is not mediated via the respiratory system. It is argued that NO acts, in contrast to O₂, not only at the radiation chemical level, but also by influencing metabolic pathways.