東京大学 工学部 アイソトープ総合センター
東京大学 工学部 原子力研究総合センター
University of Texas Health Science Center Department of Otolaryngology
宇宙科学研究所 宇宙基地利用研究センター
宇宙科学研究所 宇宙基地利用研究センター
Dalhousie University Department of Anatomy and Neurobiology
島根大学 理学部 生物科学科
宇宙開発事業団
著者所属（英）
University of Tokyo Radioisotope Center, Faculty of Engineering
University of Tokyo Research Center for Nuclear Science and Technology, Faculty of Engineering
University of Texas Health Science Center Department of Otolaryngology
Institute of Space and Astronautical Science Space Utilization Research Center
Institute of Space and Astronautical Science Space Utilization Research Center
Dalhousie University Department of Anatomy and Neurobiology
Shimane University Department of Biology, Faculty of Sciences
National Space Development Agency of Japan
出版者
宇宙開発事業団
出版者（英）
National Space Development Agency of Japan (NASDA)
Behaviors and postures of the fish medaka (Oryzias latipes) (adult) and the newt (Cynops pyrrhogaster) (adult and larvae) were observed under microgravity during the parabolic flight. Results and discussions were as follows. Medaka: the experiments were done on the adult fish of five different inbred strains and one variety of the species. Among all the inbred strains tested, three strains (HO5, HO4C, HB12A) showed looping (together with twisting) behavior under microgravity and light conditions. The strain HNI-2 did not show any looping behavior at all. Most fish of the strain HB32C did not loop either, though some of them did. The variety showed no sign of looping either. Thus, there existed a clear strain-difference in the behavioral response of the fish under microgravity and light conditions. However, under microgravity and dark conditions, all the fish tested, i.e., all the fish of the five inbred strains and the variety did loop. At present, from these parabolic flight data, the best fish candidates for the space experiments are those of HNI-2 strain. Newt: an adult newt in water swam with gentle rolling and twisting. Several developmental stage of larvae were flown. Later-stage (54-57) larvae tend to respond both at the onset and during periods of microgravity with vigorous upward or sideways swimming. Responses to hypergravity are not frequent or vigorous. Approximately 1/3 of early-stage larvae (42-48) respond to the onset of microgravity with upward swimming. These responses are more vigorous and long-lasting in light than in dark. Vigorous responses to hypergravity, either before or after microgravity, were seen in both light and dark. In dark, the most common response was to either freeze throughout the period of microgravity or to make a short movement, either upward or sideways, and then to freeze. The observations made during these parabolic flights suggest that the differences in behavior might be related to the development of the semicircular canals. Several species of amphibians were exposed to the parabolic flight to test the possibility of getting motion sickness in amphibians. Japanese tree frogs (Hyla japonica) were flown to the space station MIR. On the MIR, frogs on a surface often bent their neck backward and walked backwards. This behavior was observed on present parabolic flights and resembles the retching behavior of sick frogs on land a possible indicator of motion sickness. These results indicate that frogs can get motion sickness and suggest that the unusual posture of the frogs on the MIR may have represented motion sickness.
イモリ・メダカの微小重力下での行動 その2:両生類におけるMotion Sicknessの可能性 その1
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