Effects of γ-Ray Irradiation on Olfactory Adaptation to Benzaldehyde in Caenorhabditis elegans

Learning impairment following ionizing irradiation is an important potential risk for astronauts. Using Caenorhabditis elegans as a model organism for studying the nervous system, we previously showed that ionizing radiation affected salt chemotaxis learning behavior only at the transition stage of learning conditioning, which induced additional decreases in chemotaxis to NaCl immediately after irradiation. In the present study, we investigated the effects of γ-ray irradiation on olfactory adaptation to benzaldehyde, in which animals show a decrease in chemotaxis to benzaldehyde. Irradiation during the conditioning for adaptation to benzaldehyde did not induce an additional decrease in chemotaxis immediately after irradiation. On the other hand, at 1 h after irradiation, the progress of adaptation to benzaldehyde was interrupted by irradiation with the highest dose. These results indicate that impaired olfactory adaptation to benzaldehyde following irradiation is different from salt chemotaxis learning in C. elegans. Our findings suggest that the profile of radiation-induced response depends on the function of the nervous system in C. elegans.