Swelling of Calyx-Like Nerve Endings in Maculae and Cristae of Quail Embryos Exposed to Weightlessness

Effect of hypodynamia on structure of vestibular apparatus in Japanese quail chicks: light microscopy

“…The reason for these differences is not known but authors of these findings assumed that their possible causation could be an altered ionic metabolism of the inner ear fluids in weightlessness (Lychakov et al 1993). Based on our results, we suppose that dilatations of hair cells were caused by an increased number of ribbon synapses rather than a consequence of partly changed intensity of gravity in conditions of hypodynamia.…”

“…By contrast, no substantial disturbance or delay in the formation of the vestibular apparatus was observed in Japanese quail embryos developed in weightlessness aboard the Mir space station from 1 to 12 days of age, although there was one distinct difference in the structural organization of the maculae and cristae between the quail developing in weightlessness as compared to control group (Lychakov et al 1993).…”

“…The development and structural organization of the vestibular receptors under earthly conditions was described (Money et al 1974;Fermin et al 1998). However, fewer data are available from the studies of the influences of real microgravity on structure of vestibular apparatus in birds (Lychakov et al 1993;Kenyon et al 1995;Fermin et al 1996), and therefore further information may be provided by the ground-based model of simulated weightlessness (hypodynamia). The first experiment to examine the effects of hypodynamia on the organism of Japanese quail was carried out on adult birds (Juráni et al 1983).…”

Development of Vestibular Systems in Altered Gravity

“…16.9). The swollen shapes of the cup-like nerve endings of type I cells observed after seven days of space flight aboard Cosmos 1667 also indicated synaptic modifications in adult rats (Lychakov et al, 1993).…”

Functional Development of the Small Intestine of Japanese Quail Hatched on Mir Orbital Station

“…It was observed that after a short-term space flight adult quails displayed only reversible ultrastructural changes in the tissues of the skeletal muscle, testes and kidneys (Koãi‰ová et al 1993;Cigánková et al 1993), and the microstructure of the small intestine as well as spontaneous feeding of the birds were not seriously impaired (Koãi‰ová et al 1993;Ko‰Èál et al 1993). On the other hand, nonphysiological conditions of space flight during embryogenesis lead to a lower hatching rate, higher frequency of deviations in organ and brain development Guryeva et al 1993;Lychakov et al 1993), and to disturbances in the locomotor activity and in consequence in inability to feed properly after hatching in these quails (Boìa et al 1991;Ko‰Èál et al 1993).…”