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FACTORS AFFECTING DEVELOPMENT UNDER HYPER-GRAVITY.  B. Ladd¹, K. Nguon¹ , Victor A. Sulkowski² and E.M. Sajdel-Sulkowska^{1, 3}; Department of Psychiatry, Brigham and Women’s Hospital¹, College of William and Mary² and Harvard Medical School³, Boston, MA 02115, USA.

   The present study examines the development of rats exposed to altered gravity in order to assess the potential risks associated with reproduction and growth in space, which are crucial to long-term space habitation.  Our earlier studies suggested that pregnant rat dams exposed to chronic centrifugation at 1.5 G gained less weight, consumed less food and gave birth to smaller pups as compared to stationary controls, suggesting that undernutrition cannot be easily dismissed. In this report we focus on several factors associated with repeated chronic exposure to centrifugation that may affect the progression of pregnancy and early embryonic development. Dams were exposed to the centrifugation in the NASA-ARC 24-ft facility and gravity gradient of 1.0G to 1.75G from day nine of pregnancy, delivered and nursed their offspring until postnatal day 21. Dams lost weight during the first few days of centrifugation; the relative mass gain at 1.75G was decreased by 54.4% as compared to stationary controls at the end of the first week of centrifugation. The reduction in body weight was associated with a 28.2% reduction in the relative food consumption in these dams. Several factors such as gravitational force, angular acceleration, the Coriolis force and daily acceleration/deceleration are known to result in motion sickness and associated nausea in man and may cause similar phenomena in the rats exposed to centrifugation. Motion sickness is likely to contribute to reduced food consumption and weight gain in centrifuged dams and affect the pregnancy outcome. Motion sickness in centrifuged dams appears to be accompanied by disturbances in motor coordination and movement as observed by video recording. The relative contribution of these factors must be considered when addressing the mechanisms involved in the effect of altered gravity on mammalian development.

(Supported by NIH ES11946-01)