Altered gravitational forces affect the development of the static vestibuloocular reflex in fish (Oreochromis mossambicus)

Sebastian, C.; Eßeling, K.; Horn, Ernst-Peter

doi:10.1002/1097-4695(200101)46:1<59::aid-neu6>3.0.co;2-x

Cited by 34 publications

(22 citation statements)

References 38 publications

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“…Significant differences were also obtained for the rVOR gain. The augmentation of the rVOR in microgravity tadpoles with respect to the 1g-ground controls resembled the observation in fish (Oreochromis mossambicus) after a 9-day space flight and points to a sensitization of the neuronal network underlying the rVOR (Sebastian et al, 2001).…”

Section: Tadpoles From the Andromède Mission To The International Spasupporting

confidence: 75%

“…The most likely mechanism for reflex augmentation in the older tadpoles (cf. Fig.·7) is sensitization of the vestibular system by gravity deprivation, as also shown in bullfrogs (Bracchi et al, 1975), fish (Boyle et al, 2000;Sebastian et al, 2001;Wiederhold et al, 2003) and men (Clément et al, 2001). Recordings from the vestibular nerve of bullfrogs during microgravity revealed an initial depression of spontaneous activity but a recovery and overcompensation during ongoing microgravity exposure (Bracchi et al, 1975).…”

Section: Discussionmentioning

confidence: 67%

“…Previous studies in Xenopus and the fish Oreochromis mossambicus have shown that the rVOR amplitude is a sensitive indicator to describe: (1) modifications of the rVOR during its development Sebastian and Horn, 1999), (2) the extent of vestibular compensation after hemilabyrinthectomy , and (3) susceptibility changes within the vestibuloocular system to altered gravity Sebastian et al, 1996;Sebastian and Horn, 1998;Sebastian et al, 2001). …”

Section: Microgravity Exposurementioning

confidence: 99%

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Microgravity-induced modifications of the vestibuloocular reflex inXenopus laevistadpoles are related to development and the occurrence of tail lordosis

Horn

2006

Journal of Experimental Biology

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SUMMARY During space flights, tadpoles of the clawed toad Xenopus laevisoccasionally develop upward bended tails (tail lordosis). The tail lordosis disappears after re-entry to 1g within a couple of days. The mechanisms responsible for the induction of the tail lordosis are unknown;physical conditions such as weight de-loading or physiological factors such as decreased vestibular activity in microgravity might contribute. Microgravity(μg) also exerts significant effects on the roll-induced vestibuloocular reflex (rVOR). The rVOR was used to clarify whether tail lordosis is caused by physiological factors, by correlating the occurrence ofμ g-induced tail lordosis with the extent of μg-induced rVOR modifications. Post-flight recordings from three space flights (D-2 Spacelab mission,STS-55 in 1993; Shuttle-to-Mir mission SMM-06, STS-84 in 1997; French Soyuz taxi flight Andromède to ISS in 2001) were analyzed in these experiments. At onset of microgravity, tadpoles were at stages 25-28, 33-36 or 45. Parameters tested were rVOR gain (ratio between the angular eye movement and the lateral 30° roll) and rVOR amplitude (maximal angular postural change of the eyes during a 360° lateral roll). A ratio of 22-84% of tadpoles developed lordotic tails, depending on the space flight. The overall observation was that the rVOR of tadpoles with normal tails was either not affected by microgravity, or it was enhanced. In contrast, the rVOR of lordotic animals always revealed a depression. In particular, during post-flight days 1-11, tadpoles with lordotic tails from all three groups (25-28, 33-36 and 45) showed a lower rVOR gain and amplitude than the 1g-controls. The rVOR gain and amplitude of tadpoles from the groups 25-28 and 33-36 that developed normal tails was not affected by microgravity while the rVOR of μg-tadpoles from the stage-45 group with normal tails revealed a significant rVOR augmentation. In conclusion: (1)the vestibular system of tadpoles with lordotic tails is developmentally retarded by microgravity; (2) after a critical status of vestibular maturation obtained during the appearance of first swimming, microgravity activates an adaptation mechanism that causes a sensitization of the vestibular system.

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Section: Tadpoles From the Andromède Mission To The International Spasupporting

confidence: 75%

Section: Discussionmentioning

confidence: 67%

Section: Microgravity Exposurementioning

confidence: 99%

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Microgravity-induced modifications of the vestibuloocular reflex inXenopus laevistadpoles are related to development and the occurrence of tail lordosis

Horn

2006

Journal of Experimental Biology

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“…Agosti et al, 1986;Rohregger and Dieringer, 2002;Horn et al, 1986b;Horn, 2006)]. The underlying vestibular networks that connect the peripheral sensory structures with the neuronal and muscular elements are formed during development under the influence of environmental, in particular gravitational, conditions (Moorman et al, 1999;Moorman et al, 2002;Sebastian et al, 2001;Horn and Gabriel, 2011) and genetic factors. Genetics factors were mainly studied for the development of otoliths in zebrafish and include contributions of otoc1 (Petko et al, 2008), zOMP-1 (Murayama et al, 2005), pax5 (Kwak et al, 2006) and starmaker (Söllner et al, 2003;Söllner et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…This curve was used to calculate the rVOR amplitude, which is the maximal peak-to-peak movement of the eyes during a 360deg lateral roll. Previous studies in Xenopus laevis, young fish (Oreochromis mossambicus) and salamander larvae (Pleurodeles waltl) have shown that the rVOR amplitude is a sensitive indicator to describe (1) modifications of the rVOR during development (Horn et al, 1986a;Sebastian and Horn, 1999;Gabriel et al, 2012), (2) the susceptibility to changes within the vestibuloocular system induced by vestibular lesions (Horn et al, 1986b), (3) the extent of vestibular plasticity after such lesions (Rayer and Horn, 1986) and (4) the impact of altered gravitational conditions on vestibular function (Horn 2006;Sebastian et al, 2001;Horn and Gabriel, 2011;Gabriel et al, 2012). The rVOR amplitude was determined by the angular difference between the mean of eye angles recorded for roll angles between 60deg to 120deg and 240deg to 300deg, respectively (cf.…”

Section: Recordings Of the Rvormentioning

confidence: 99%

The vestibuloocular reflex of tadpoles (Xenopus laevis) after knock-down of the isthmus related transcription factor XTcf-4

Horn

El-Yamany

Gradl

2012

Journal of Experimental Biology

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The Sensitivity of an Immature Vestibular System to Altered Gravity

Gabriel

Frippiat²,

Frey

et al. 2012

J. Exp. Zool.

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Stimulus deprivation or stimulus augmentation can induce long-lasting modifications to sensory and motor systems. If deprivation is effective only during a limited period of life this phase is called "critical period." A critical period was described for the development of the roll-induced vestibuloocular reflex (rVOR) of Xenopus laevis using spaceflights. Spaceflight durations and basic conditions of Xenopus' development did not make it possible to answer the question whether exposure of the immature vestibular organ to weightlessness affects rVOR development. The embryonic development of Pleurodeles waltl is slow enough to solve this problem because the rVOR cannot be induced before 15 dpf. Stage 20-21 embryos (4 dpf) were exposed to microgravity during a 10-day spaceflight, or to 3g hypergravity following the same time schedule. After termination of altered gravity, the rVOR was recorded twice in most animals. The main observations were as follows: (1) after the first rVOR appearance at stage 37 (16 dpf), both rVOR gain and amplitude increased steadily up to saturation levels of 0.22 and 20°, respectively. (2) Three days after termination of microgravity, flight and ground larvae showed no rVOR; 1 day later, the rVOR could be induced only in ground larvae. Differences disappeared after 3 weeks. (3) For 10 days after 3g exposure, rVOR development was similar to that of 1g-controls but 3 weeks later, 3g-larvae showed a larger rVOR than 1g-controls. These observations indicate that the immature vestibular system is transiently sensitive to microgravity exposure and that exposure of the immature vestibular system to hypergravity leads to a slowly growing vestibular sensitization.

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Altered gravitational forces affect the development of the static vestibuloocular reflex in fish (Oreochromis mossambicus)

Cited by 34 publications

References 38 publications

Microgravity-induced modifications of the vestibuloocular reflex inXenopus laevistadpoles are related to development and the occurrence of tail lordosis

Microgravity-induced modifications of the vestibuloocular reflex inXenopus laevistadpoles are related to development and the occurrence of tail lordosis

The vestibuloocular reflex of tadpoles (Xenopus laevis) after knock-down of the isthmus related transcription factor XTcf-4

The Sensitivity of an Immature Vestibular System to Altered Gravity

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