Abstract |
Although autoradiography has demonstrated local incorporation of (3H)inositol into axonal phospholipids after intraneural injection (Gould, 1976; Gould et at., 1987b), retrograde axonal transport of phosphatidylinositol has only been demonstrated after injection of lipid precursor into the cell body regions (L4 and L5 dorsal root ganglia: DRGs) of the sciatic nerve (Armstron et al, 1985). The authors now report the retrograde axonal transport of inositol phospholipids synthesized locally in the axons. Following microinjection of myo-(3H)inositol into the rat scietic nerve (50-55 mm distal to L4 and L5 DRGs), a time-dependent accumulation of (3H)label occurred in the DRGs ipsilateral (lipsiDRGs to the injection site. The time course of appearance of labeled lipids in the ipsilateral DRGs after injection of precursor into the nerve at various distances from the DRGs indicated a transport rate of at least 5mm/hr. Accumulation of label in the DRGs could be prevented by intraneural injection of colchicine or ligation of the sciatic nerve between the DRGs and the isotope injection site. These results demonstrate that inositol phospholipids synthesized locally in the sciatic nerve are retrogradely transported back to the nerve cell bodies located in the DRG. |