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INTEGRATED PHYSIOLOGY - Its Competition and Cooperation with Molecular and Genetic Research.    E.R. Horn. Gravitational Physiology, Ulm University, Ulm, Germany

   Organisms are composed of organs and tissues that were formed and connected during development according to genetic programs and environmental factors. During the last two decades, molecular and genetic aspects have pushed integrated (systemic) approaches into the background, leading sometimes to a feeling that organisms are only the sum of cells or molecules. However, central integration between all structures and compartments of a body is mandatory for the functional stability of the organism. Thus, the general requirements for modern life science research are (1) to describe facts related to the whole body, and (2) to analyse underlying molecular and genetic mechanisms in a combined manner. Space Life Science Research offers the unique possibility to keep thinking about integrated Physiology alive due to the driving force of making spaceflight safe for men, and to develop not only physical but also pharmacological countermeasures in case of microgravity-induced disturbances of the integrated system (i.e., the organism). - Some flight and ground-based studies will be discussed in the frame of INTEGRATED PHYSIOLOGY and MOLECULAR BIOLOGY. Pompeiano and his team (Pisa) have identified changes in early gene expression in specific brain areas of microgravity-exposed rats that might be important in adaptive gain changes of vestibular and vegetative function. Ground-based studies in birds by Anokhin and colleagues (Moscow) postulated that acquisition of new experience is related to early gene expression in the brain which might be basis of adaptation to new environmental conditions such as microgravity. Own studies with tadpoles after knock-down of a transcription factor of the wnt-pathway revealed similarities in their phenotype with that of microgravity exposed tadpoles leading to the conclusion that growth factor gradients in the embryo are modified by microgravity. Thus, integrated physiology will benefit from molecular approaches, and most important, vice versa. - Space projects of Horn were supported by DLR.