Axonal transport of gangliosides in the visual system of the developing chick embryo

Chick embryos aged 7-18 days of development were injected with N-[ (3)H] acetylmannosamine into one eye. The labeling of gangliosides was significantly higher in the contralateral- than in the ipsilateral-optic tectum in embryos aged 14 days or older. Comparison of the radioactivities of thin-layer chromatograms of gangliosides from the contralateral- and ipsilateral-optic tecta showed that in the 14-day-old embryo about 56 and 29% of the transported radioactivity chromatographed as GD1a and GT1, respectively. Most of the remaining radioactivity chromatographed in the zone of less complex gangliosides (GM2-GD3, 3%; GM3, 6%). In the 18-day-old embryo about 72% of the transported radioactivity chromatographed as GD1a; the radioactivity in the zone of GT1 was reduced to about 2% and that in the less complex gangliosides remained low (about 14% in the zone of GM2-GD3 and 7% in the zone of GM3).