title: Protection and potentiation of radiation clastogenesis by caffeine: nature of possible initial events.
abstract: Data on the differential modification of the oxic and anoxic components of radiation clastogenesis by caffeine already published in the literature have been briefly reviewed, additional unpublished data relevant for consideration of possible mechanisms have been presented and the possible events in terms of radiation chemistry have been discussed. It is considered that radioprotection against oxic component possibly results from the competition of caffeine with oxygen for e-aq, whereas radiosensitization of the anoxic component is, at least partly, due to restoration of physico-chemical environment achieved by oxygen alone in the irradiated cells. These reactions involve eaq-, oOH and H2O2 formed in the cells exposed to ionizing radiation.
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D000818:Animals; D002110:Caffeine / Q000633:toxicity*; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D009154:Mutation / Q000187:drug effects* / Q000528:radiation effects; D010053:Ovary; D012639:Seeds; D014867:Water
chemical_list: D014867:Water; D002110:Caffeine