A morphometric and computer‐assisted three‐dimensional reconstruction study of neural tube formation in chick embryos

Robert G. Nagele, Kevin T. Bush, Francis J. Lynch, Hsin‐Yi ‐Y Lee

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The origin of the driving forces for neural tube formation remains uncertain but is currently thought to involve the participation of microfilament bundles situated in the apical ends of neuroepithelial cells. In the work presented here, we show how morphometric measurements that map local variations in the apical geometry of neuroepithelial cells (especially apical constriction) can provide information on the distribution of motive forces within the neuroepithelium during neural tube formation. When used in combination with computer‐assisted, three‐dimensional reconstruction, it becomes possible to analyze the morphometric data from a dynamic, three‐dimensional perspective. As an example application of this method, we have used morphometry to evaluate the effects of ionomycin on the developing neuroepithelium. Treatment of early (stages 6‐8) chick embryos with 5 μM ionomycin was found to cause rapid bending of the neuroepithelium within 1 min of exposure and a dramatic acceleration of the normal sequence of neural tube formation. Electron microscopy and morphometry revealed that this acceleration was coincident with a marked increase in the local degree of apical constriction of neuroepithelial cells, presumably a consequence of enhanced contractile activity of apical microfilament bundles. This work shows that transient elevation of free calcium levels can accelerate the usualal sequential phases of NT formation. The rapidity of the response (hours of normal development reduced to minutes), increased prominence of apical microfilament bundles, and the enhanced degree of apical constriction strongly support a direct causal role for apical microfilament bundles and apical constriction of neuroepithelial cells in bending of the neuroepithelium.

Original languageEnglish (US)
Pages (from-to)425-436
Number of pages12
JournalThe Anatomical Record
Volume231
Issue number4
DOIs
StatePublished - Dec 1991

All Science Journal Classification (ASJC) codes

  • Anatomy
  • Agricultural and Biological Sciences (miscellaneous)

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