Contribution of axonal transport to the renewal of myelin phospholipids in peripheral nerves. II

The classes of radioactive phospholipids appearing in the ciliary ganglion (CG) and especially in the myelin sheath of the intraorbital part of the oculomotor nerve (OMN) were determined after the intracerebral injection of [2-3H]glycerol and [methyl-14C]choline to chickens. Analysis of the radioactive compounds in water-soluble fractions and chloroform-methanol extracts was performed by thin-layer chromatography (TLC). The water-soluble content of the OMN and CG was much poorer in [2-3H]glycerol and metabolites than in [methyl-14C]choline and derivatives. All classes of glycerophospholipids were found to be axonally transported along the OMN and into the CG, but choline-phosphoglycerides (CPG) were largely predominant. In myelin fractions from the OMN, the specific radioactivity (SRA) of CPG labeled with [2-3H]glycerol reached a maximum earlier (40 h) than the SRA of CPG labeled with [methyl-14C]choline. A 25-fold enhancement of the [14C]SRA of sphingomyelin (SM) was observed between 12 h and 7 days. (Auth.)