Factors determining the morphology and distribution of astrocytes in the cat retina: A ‘contact-spacing’ model of astrocyte interaction
Article first published online: 9 OCT 2004
Copyright © 1991 Wiley-Liss, Inc.
Journal of Comparative Neurology
Volume 303, Issue 3, pages 387–399, 15 January 1991
How to Cite
Chan-Ling, T. and Stone, J. (1991), Factors determining the morphology and distribution of astrocytes in the cat retina: A ‘contact-spacing’ model of astrocyte interaction. J. Comp. Neurol., 303: 387–399. doi: 10.1002/cne.903030305
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
- Manuscript Accepted: 28 SEP 1990
- neuronal-glia interactions;
- ganglion cells;
- retinopathy of prematurity
The retina provides a valuable opportunity to examine the interaction of astrocytes with neurones and vasculature, in adult tissue and in vivo. We have studied astrocytes in cat retina to delineate the interactions that determine their morphology and distribution. Their morphology varied with their interaction with surrounding cells, from a classic stellate shape to an elongated bipolar form associated with axon bundles. Evidence is presented that the distribution of astrocytes across the retina is determined by their morphology and by a previously unrecognised interaction between astrocytes, which we term ‘contact-spacing’ in which astrocytes maintain contact with their neighbours through their processes, but keep their somas apart. Evidence is also presented that astrocytes are not influenced in their distribution by surrounding neurones, and the influence of developmental mechanisms is identified. These observations are summarised in a contact-spacing model of astrocyte distribution, and four predictions of the model are tested. The concentration of astrocytes along axon bundles dispersed when the axons degenerate but not when vessels were prevented from forming. Further, when both axons and vessels were eliminated, the concentrations of astrocytes dispersed and they became stellate in form. Finally, in the retina of the rat, in which astrocytes show no affinity for axons, the distribution of astrocytes is essentially uniform. We suggest that the contact-spacing interaction among astrocytes provides the anatomical basis of a functional glial network extending across the retina and throughout the central nervous system.