Affiliations: [a] Department of Otolaryngology, Faculty of Medicine, Osaka University, Osaka 565, Japan | [b] Department of Medical Physics, Faculty of Medicine, Osaka University, Osaka 565, Japan | [c] Department of Pharmacology, Ehime University School of Medicine, Ehime 791-02, Japan
Note: [*] Reprint address: Noriaki Takeda, M.D., Ph.D., Department of Otolaryngology, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565, Japan. Tel: +81-6-879-3951; Fax: +81-6-879-3959.
Abstract: We examined the effect and aftereffect of acute or chronic load of hypergravity produced by an animal centrifuge, on pica (that is, kaolin intake) in the rat as an index of motion sickness. Although the degree of pica initially induced by acute or chronic hypergravity was not different, the rate of decline of increased kaolin intake over poststimulus days was different. Pica after a 1-h load of 2g decreased rapidly. On the other hand, pica lasted 3 days after a 48-h load of 2g. These findings suggest that the aftereffects of chronic hypergravity application on pica are due to motion sickness induced by readaptation to normal gravity, and they support our idea that after adaptation to a hypergravity environment, return and readaptation to the normal gravity can simulate exposure and adaptation to microgravity. We concluded that motion sickness in rats induced by the aftereffects of chronic hypergravity stimulation can be used as a ground-based animal model of space adaptation syndrome.
Keywords: space adaptation syndrome, motion sickness, hypergravity, pica, rat
