RETINAL GANGLION-CELL AXONS DRIVE THE PROLIFERATION OF ASTROCYTES IN THE DEVELOPING RODENT OPTIC-NERVE

We show that the proliferation of astrocytes in the developing rodent optic nerve absolutely depends on axons and that this axonal influence depends on axonal transport but not on axonal electrical activity. We also show that purified retinal ganglion cells stimulate DNA synthesi s in optic nerve astrocytes in culture and that the effect can be mimi cked by fibroblast growth factor but not by neuregulins or several oth er growth factors. Taken together with previous findings, our present results indicate that axons promote glial cell proliferation and survi val in the developing optic nerve by at least three distinct mechanism s.