Ca2+ signalling and gap junction coupling within and between pigment epithelium and neural retina in the developing chick.

Autor: Pearson, Rachael A., Catsicas, Marina, Becker, David L., Bayley, Philippa, Lüneborg, Nanna L., Mobbs, Peter
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Zdroj: European Journal of Neuroscience; May2004, Vol. 19 Issue 9, p2435-2445, 11p
Abstrakt: Development of the neural retina is controlled in part by the adjacent retinal pigment epithelium (RPE). To understand better the mechanisms involved, we investigated calcium signalling and gap junctional coupling within and between the RPE and the neural retina in embryonic day (E) 5 chick. We show that the RPF and the ventricular zone (VZ) of the neural retina display spontaneous Ca2+ transients. In the RPF, these often spread as waves between neighbouring cells. In the VZ, the frequency of both Ca2+ transients and waves was lower than in RPF, but increased two-fold in its presence. Ca2+ signals occasionally crossed the boundary between the RPF and VZ in either direction. In both tissues, the frequency of propagating Ca2+ waves, but not of individual cell transients, was reduced by gap junction blockers. Use of the gap junction permeant tracer Neurobiotin showed that neural retina cells are coupled into clusters that span the thickness of the retina, and that RPF cells are both coupled together and to clusters of cells in the neural retina. Immunolabelling for Cx43 showed this gap junction protein is present at the junction between the RPF and VZ and thus could potentially mediate the coupling of the two tissues. Immunolabelling for β-tubulin and vimentin showed that clusters of coupled cells in the neural retina comprised mainly progenitor cells. We conclude that gap junctions between progenitor cells, and between these cells and the RPF, may orchestrate retinal proliferation/differentiation, via the propagation of Ca2+ or other signalling molecules. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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