XENOPUS TEMPORAL RETINAL NEURITES COLLAPSE ON CONTACT WITH GLIAL-CELLS FROM CAUDAL TECTUM INVITRO

Nasal and temporal retinal neurites were confronted in culture with glial cells from the rostral and caudal parts of the optic tectum and with glial cells from the diencephalon. Twenty of each of the six classes of encounter between individual growth cones and isolated glial cells were analysed by time-lapse videorecording. The results show that growth cones from the temporal retina collapse when they contact glial cells from the caudal tectum, but do not collapse when they contact glia from other areas. Growth cones of nasal retinal fibres do not collapse on contact with any of the glial types examined. This suggests that the inhibitory phenomena described by others are in part due to the cell surface characteristics of glial cells, and that there are differences between glia from the front and back of the optic tectum.