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Abstract
Free‐running circadian rhythms of locomotor activity of Tenebrionid beetles Trigonoscelis gigas Reitt., taken from the Turkmenian sand desert, were monitored in DD. The effects of microgravity (μG) ‐11 days in space flight aboard the Russian BION‐10 “COSMOS”; satellite, and of 2G hypergravity ‐ seven days on a centrifuge, were determined.
Two kinds of effects were found.
In stable 2‐peak records, there was a moderate decrease of τ in μG and an increase of τ in 2G, both of about 0.3 hr.
In unstable records, alterations of gravity caused drastic deviations of τ and ϕ. Remarkably, two peaks of the activity rhythm, which are supposed to be controlled by separate oscillators, responded to gravity transitions in different ways.
Gravity effects on the circadian system could be explained from a direct effect on the oscillator(s) itself or from a feed‐back by altered locomotion to the pacemaker.
Thus, for the first time the gravity dependence of a free‐running circadian rhythm was proved in a combination of real space flight and centrifuge experiments.
Notes
Institute of Biomedical Problems, 123007 Moscow, Khoroshevskoye shosse 76‐A, Russia.
Department of Physiology, University of Leiden, POBox 9604, 2333 AL Leiden, The Netherlands.∗
Department of Biology, University of Alma‐Ata, Kazakhstan.
Correspondence
