Effects of ionizing radiation on locomotory behavior and mechanosensation in Caenorhabditis elegans.
Locomotory behavior (motility) and mechanosensation are of vital importance in animals. We examined the effects of ionizing radiation (IR) on locomotory behavior and mechanosensation using a model organism, the nematode Caenorhabditis elegans. Bacterial mechanosensation in C. elegans induces the dopamine-mediated slowing of locomotion in the presence of bacteria (food), known as the basal slowing response. We previously reported an IR-induced reduction of locomotory rate in the absence of food. In the present study, we observed a similar IR-induced reduction of locomotory rate in the cat-2 mutant, which is defective in bacterial mechanosensation. The dose response pattern of the locomotory rate in the presence of food was relatively flat in wild-type animals, but not in cat-2 mutants. This suggests that the dopamine system, which is related to bacterial mechanosensation in C. elegans, might have a dominant effect on locomotory rate in the presence of food, which masks the effects of other stimuli. Moreover, we found that the behavioral responses of hydrogen peroxide-exposed wild-type animals are similar to those of IR-exposed animals. Our findings suggest that the IR-induced reduction of locomotory rate in the absence of food is mediated by a different pathway from that for bacterial mechanosensation, at least partially through IR-produced hydrogen peroxide.
Suzuki
Michiyo
M
Japan Atomic Energy Agency, Watanuki, Takasaki, Gunma, Japan. michiyosuzuki@ieee.org
Sakashita
Tetsuya
T
Yanase
Sumino
S
Kikuchi
Masahiro
M
Ohba
Hirofumi
H
Higashitani
Atsushi
A
Hamada
Nobuyuki
N
Funayama
Tomoo
T
Fukamoto
Kana
K
Tsuji
Toshio
T
Kobayashi
Yasuhiko
Y
D000818:Animals; D001522:Behavior, Animal / Q000528:radiation effects; D017173:Caenorhabditis elegans / Q000528:radiation effects*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology; D002628:Chemoreceptor Cells / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D008124:Locomotion / Q000528:radiation effects*; D008954:Models, Biological; D009043:Motor Activity / Q000528:radiation effects*; D009154:Mutation; D018384:Oxidative Stress; D011839:Radiation, Ionizing; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics* / Q000502:physiology
D029742:Caenorhabditis elegans Proteins; D006861:Hydrogen Peroxide; D014446:Tyrosine 3-Monooxygenase