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We studied the rhythmic contractions of the amnion in the developing chick eggs at the different developmental stages, using sensitive mechanosensors, connected with amniotic membrane. The recordings were carry out in normal conditions (37.5oC) and under the short-term changes of the some environmental factors (the temperature lowering, acute hyperoxia, hypercapnia and hypoxia with the different content of O2) with the continuous registration of the amnion rhythmic contractions.
It has been demonstrated that during the gas application for 10 min the high concentration of CO2 (2%) inhibited and O2 (100%) accelerated the amnion contractions. Acute hypoxia (10 and 15% O2) during 10-20 min inhibited or arrested the amnion contractions. The lowering of the temperature slowly decreased the frequency of amnion contraction, which stopped at 30o- 32 o C. All these changes of the amnion rhythmic contractions under the short-term influence of these environmental factors were reversible and the frequency of the amnion contractions restored to the initial level after the returning to the normal conditions.
These data have shown that the amnion rhythmic contractions are involved in the short-term response of the developing embryo on the environmental factors studied and allows to suggest their participation in the environmental adaptation during embryonic development. It remains unclear, however, how the revealed changes in amnion contractile activity might influence the embryo development and what mechanisms underling these effects. As the amnion contractions provide the mixing of the amniotic fluid surrounding the embryo, we propose, that in combination with the other factors the changes in the amnion contractile activity could influence the level of the metabolic processes in the developing egg. 1Institute of developmental Biology RAS , Moscow, Russia, 2 Institute of Veterinary Physiology,Free University Berlin