Short term labeling of proteins, gangliosides and glycoproteins of the optic tract of chickens exposed to light or darkness

Abstract

In contrast with previous findings of the labeling of the glycosidic moieties of the gangliosides and glycoproteins in chickens injected with N-[ (3)H ] acetylmannosamine , the labeling of the ganglion cell layer and optic tectum proteins of chicks exposed to light after an intraocular injection of [(3)H]proline showed no differences with those of their counterpart chickens that remained in darkness. The same failure in finding a difference was met when the cytosolic or the particulate proteins or the acid soluble fraction in the retina were compared. Cycloheximide and puromycin inhibited the labeling of retina and optic tectum proteins, gangliosides and glycoproteins in both illumination conditions. Since the labelings in the optic tectum appeared more inhibited than those in the retina ganglion cell layer it was concluded that cycloheximide and puromycin, besides the synthesis of those compounds, also inhibit their axonal transport. On the basis of these contrasting results the working hypothesis is advanced that light stimulation enhances the activity of the Golgi apparatus but not (or less) that of the polyribosomes.