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RETROGRADE AXONAL TRANSPORT OF PHOSPHOINOSITIDES AFTER INTRANEURAL INJECTION OF [3H]MYO-INOSITOL INTO THE RAT SCIATIC NERVE
Citation:
Padilla, S. AND C. Pope. RETROGRADE AXONAL TRANSPORT OF PHOSPHOINOSITIDES AFTER INTRANEURAL INJECTION OF [3H]MYO-INOSITOL INTO THE RAT SCIATIC NERVE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-91/200 (NTIS PB91242594), 1991.
Description:
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). e now report the retrograde axonal transport of inositol phospholipids synthesized locally in the axons. ollowing microinjection of myo-[3H]inositol into the rat sciatic 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. he ratio of dpm present in the ipsiDRGs to that in the contralateral DRGs was not significantly different from unity between 2 and 8 hours after isotope injection, but increased to values of 10 to 12 between 24 and 72 hours following precursor injection. y 24 hours following precursor injection the ipsilateral/contralateral ratio of the water-soluble label in the DRGs still remained around 1.0, while the corresponding ratio in the chloroform/methanol-soluble fraction was approximately 20. he 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. ccumulation 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. hese results demonstrate that inositol phospholipids synthesized locally in the sciatic nerve are retrogradely transported back to the nerve cell bodies located in the DRG.