Hypergravity exposure affects ventral root activity in tadpoles (Xenopus laevis).
In tadpoles, it is possible to observe the rhythmical, burstlike activity of spinal motoneurons by extracellular recordings from the ventral roots. We examined the effects of hypergravity on tadpole locomotion by using a model of fictive swimming in paralysed larvae of Xenopus laevis. Hypergravity (3g) treatment lasted 10 or 11 days. After the 3g-exposure, the mean burst duration of the 3g-animals was significantly (p < or = 0.01) increased compared to the 1g-controls. Readaptation was observed for 8 days after the end of the 3g-period. Burst duration also increases with the age of the tadpoles. Therefore, we postulate that hypergravity has a reversible effect on motor development, probably caused by a neurotrophic effect of a tonic base activity of the vestibular nuclei.
Gravitational Physiology, Department of Neurobiology, University of Ulm, Albert-Einstein-Allee, Germany. sybille.boeser@medizine.uni-ulm.de
Sybille
S
Boser
Eberhard
E
Horn