Journal of Neuroscience, Vol 14, 5035-5049, Copyright © 1994 by Society for Neuroscience
Cell adhesion molecules regulating neurite growth from amacrine and rod photoreceptor cells [published erratum appears in J Neurosci 1994 Oct;14(10):following table of contents]
IJ Kljavin, C Lagenaur, JL Bixby and TA Reh
University of Calgary, Department of Neuroscience, Alberta, Canada.
A great deal is now known about the cell adhesion molecules (CAMs) that are
responsible for promoting the growth of ganglion cell axons as they project
out of the retina through the optic nerve and finally to distant targets in
the brain. However, the CAMs important for regulating axon outgrowth from
nonprojection neurons, such as amacrine cells and rods, are not known. Such
local circuit neurons extend their neurites rather short distances on
cellular surfaces not normally encountered by the ganglion cell axons. To
study the mechanisms regulating axon or dendrite growth from local circuit
neurons, neurite outgrowth from amacrine cells and rod photoreceptor cells
derived from the rat was examined in vitro on immunopurified forms of NCAM,
L1, and N-cadherin, three well-characterized adhesive molecules found in
the developing retina. Either early (P3) or late (P10) postnatal amacrine
cells grew neurites on all three CAMs, but there were significant
differences in the percentage of the amacrine cells that responded to each
CAM. None of the CAMs supported neurite outgrowth from early postnatal
rods, but, surprisingly, NCAM stimulated vigorous neurite extension from
rods isolated at postnatal day 10. Postnatal ganglion cells were also
examined for comparison and were found not to grow neurites on NCAM, but
did grow extensive processes on L1 and N- cadherin. These results show that
NCAM, L1, and N-cadherin can promote neurite outgrowth from local circuit
neurons, but that the effectiveness of any particular CAM is dependent on
the cell type and the developmental period.