Effects of ionizing radiation on motor functions in

Suzuki, Michiyo; Sakashita, Tetsuya; Hattori, Yuya; Tsuji, Toshio*; Kobayashi, Yasuhiko

To better understand the effects of radiation inherent to human activities such as manned space flight, diagnostic imaging, and radiation therapy, it is important to focus on not only the risks of carcinogenesis but also the potential for effects on critical functions such as learning, memory and/or motor control. The nematode Caenorhabditis elegans is a good in vivo model for the examination of radiobiological effects. Using this model, we recently found that whole body irradiation reduced both the locomotion using body-wall muscles and pumping motion (chewing and swallowing) using pharyngeal muscles, and that both movements were restored within several hours. However, there was an obvious difference in the aspect of the reduction between the locomotion and pumping. Though it is well-known that heavy ions charging particles with a high linear energy transfer (LET) induce higher relative biological effectiveness than low-LET radiation such as -rays, effects of heavy ion beams on 's motility were same as those of -rays. In this presentation, we will give an outline of the radiation effects on motor functions in and discuss about further studies to understand the detailed mechanism underlying the irradiation-induced reduction and restoration of movements.