Oxidative stress suppresses locomotion and pumping motion in

Suzuki, Michiyo; Sakashita, Tetsuya; Hattori, Yuya; Kobayashi, Yasuhiko

We recently found that whole body irradiation reduced locomotion in , though the mechanisms are not clear. It is well known that free radicals such as OH and H are produced following exposure of ionizing radiation. The reactions of free radicals cause the production of oxidative stress including hydrogen peroxide (HO). Oxidative stress is known as an important factor of aging, and may relate to the decrease of motility observed in the aging process. We therefore explored the potential effectiveness of HO in the suppression of 's locomotion. Wild-type animals were exposed to graded doses of HO and the locomotory rate was evaluated. The locomotory rate was significantly decreased in HO-exposed animals, in which the dose response was similar to that in the irradiated animals. We subsequently investigated the radiation effects on the pharyngeal pumping motion (chewing and swallowing) and the involvement of oxidative stress. As a result, the proportion of the pumping-motion arrest significantly increased after whole body irradiation and the pumping-motion arrest was restored within several hours. Furthermore, the response in HO-exposed animals was similar to that in the irradiated animals. These results support the possibility that radiation-induced suppression of both locomotion and pumping motion in was caused by radiation-produced HO.