Axonal transport of intraocularly injected [ 3H-Sph]-GD 1a in the chicken optic system and the fate of the exogenous ganglioside distributed by blood

Abstract

Twelve-day-old chicks (White Leghorn) received an injection of 481 kBq (8.1 nmol) of [ 3H-Sph]-GD 1a, which was labeled in its sphingoid, into the right eye. Structures of the injected and the non-injected (control) optic system (retinae, optic nerves, chiasm, optic lobes), the cerebrum, blood, liver, kidney, and fly-muscle were analyzed 1,4,8 and 14 days later, with respect to total non-volatile radioactivity and to that bound to lower-phase lipids and gangliosides. It was demonstrated that exogenous [ 3H-Sph]-GD 1a was taken up by the retina and mainly catabolized, 3H-label, reincorporated into the lower-phase lipids and gangliosides as well as authentic exogenous [ 3H-Sph]-GD 1a were transported rapidly anterogradely in the entire optic system. [ 3H-Sph]-GD 1a, distributed via the blood stream was taken up by liver, kidney and muscle and was metabolized faster in these organs than in the retina. The cerebrum and the brain structures of the control optic system incorporated 3H-radioactivity to a much lower extent than the non-neural organs.