Neurobiological experiments on 4 animal species (Xenopus laevis, Pleurodeles waltl, Drosophila melanogaster, Acheta domesticus) were performed to study effects of microgravity on development and aging of neuronal, sensory and motor systems. Animal models were selected according to their suitability to answer questions concerning μg-effects on neuroanatomy, neuronal activity, and behaviour. The studies were performed on the Soyuz Taxi flights Andromède, Cervantes, Eneide and LDM-TMA8/TMA7. Observations from these flights include: (1) In tadpoles and cricket larvae, morphological features of sensory cells and neurons are rarely affected by microgravity. (2) In crickets, in-flight fertilization was successful; after landing, flight larvae hatched earlier than ground reared siblings. (3) In crickets, proliferation of peptidergic neurons and their projection patterns within the nervous system were not affected by microgravity. (4) During aging, the impact of microgravity on peptidergic neurons of male Drosophila was limited to the size of cell body. (5) In Xenopus, neurophysiological features of the spinal motor system during fictive swimming were partially modified. (6) In Xenopus tadpoles, the vestibuloocular reflex was affected in an age-related manner. Modifications were also related to the occurrence of a tail lordosis induced by microgravity. It is concluded that adaptation to microgravity during development and aging is mainly based on physiological mechanisms within the central nervous system while structural modifications of the sensory and neuronal system contribute less.
Research Containing: Drosophila
Human exploration of outer space will eventually take place. In preparation for this endeavour, it is important to establish the nature of the biological response to a prolonged exposure to the space environment. In one of the recent Soyuz Missions to serve the International Space Station (ISS), the Spanish Soyuz mission in October 2003, we exposed four groups of Drosophila male imagoes to microgravity during the almost eleven days of the Cervantes mission to study their motility behaviour. The groups were three of young flies and one of mature flies, In previous space experiments, we have shown that when imagoes are exposed to microgravity they markedly change their behaviour by increasing their motility, especially if subjected to these conditions immediately after hatching. The constraints of the current Soyuz flights made it impossible to study the early posthatching period. A low temperature cold transport was incorporated as a possible way out of this constraint. It turned out that on top of the space flight effects, the cold treatment by itself, modifies the motility behaviour of the flies. Although the four groups increased their motility, the young flies did it in a much lower extent than the mature flies that had not been exposed to the low temperature during transportation. Nevertheless, the flies flown in the ISS are still more active than the parallel ground controls. As a consequence of the lower motility stimulation in this experiment, a likely consequence of the cold transport step, no effects on the life spans of the flown flies were detected. Together with previous results, this study confirms that high levels of motility behaviour are necessary to produce significant decreases in fly longevity.
Multi-use Variable-gravity Platform (MVP) – Dual Centrifuges Simultaneously Providing 0-2g Each
- Cell culturing (adherent and suspended)
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