A scanning electron microscopic and flame spectrometry study on the role of Ca2+ in amphibian neurulation using papaverine inhibition and ionophore induction of morphogenetic movement
✍ Scribed by Moran, Denis J.
- Publisher
- John Wiley and Sons
- Year
- 1976
- Tongue
- English
- Weight
- 506 KB
- Volume
- 198
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
SEM observations reveal that papaverine, which interferes with Ca^2+^ flux, inhibits neural fold formation causing a flattening of the cellular surface and a broadening of cellular junctions. Ionophore A23187 and EGTA both counter this effect promoting a rapid cellular constriction which results in the formation of neural ridges and folds as individual cells become uplifted and ruffled. Flame spectrometry data indicate that as Ambystoma maculatum or mexicanum embryos neurulate Ca^2+^ is released to the medium, a condition which is impeded by papaverine. Ionophore A23187 induces Ca^2+^ influx whereas EGTA induces an efflux. Since both agents affect similar morphological changes it is suggested that the availability of free Ca^2+^ is crucial in controlling the morphogenetic movements of neurulation. It is now apparent that neuro‐axial development in the urodele is accompanied by a Ca^2+^ efflux, but the mechanism(s) responsible for the ion's release is unknown.