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LOCALLY SYNTHESIZED PHOSPHATIDYCHOLINE, BUT NOT PROTEIN, UNDERGOES RAPID RETROGRADE AXONAL TRANSPORT IN THE RAT SCIATIC NERVE
Citation:
Padilal, S., E. Bennett, P. Tandon, AND V. Wilson. LOCALLY SYNTHESIZED PHOSPHATIDYCHOLINE, BUT NOT PROTEIN, UNDERGOES RAPID RETROGRADE AXONAL TRANSPORT IN THE RAT SCIATIC NERVE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/353 (NTIS PB93228591).
Description:
Retrograde axonal transport of phosphatidylcholine (PC) in the sciatic nerve has been demonstrated only after injection of lipid precursors into the cell body regions (Armstrong et al. 1985). icroinjection of [methyl-3H]choline into the sciatic nerve results in extensive incorporation of the label into Schwann cell/myelin phospholipids with sparse axonal labeling (Gould et al., 1987a). e now report, however, that after microinjection (lu 1) of [methyl-3H [choline chloride into the rat sciatic nerve (35-40mm dual to L4 and L5 dorsal root ganglia; DRGs) time-dependent accumulation of material occurred in DRGs ipsilateral, but not contralateral, to the injection site. he level of radioactivity in the ipsilateral DRGs was minimal at 2 hrs after isotope injection, but was significantly increased at 7, 24, 48 and 72 hrs after intraneural isotope injection (n-3-8 per time point). ore than 95% of the label in the ipsilateral DRGs was present in phosphatidylcholine at @ time points. he radioactivity in the water soluble fraction did not show a time-dependent accumulation in the ipsilateral DRGs as compared to the contralateral DRGS, ruling out transport or diffusion of precursor moleculares. dditionally, colchicine injection into the sciatic nerve proximal to the isotope injection site prevented the accumulation of radiolabel in the ipsilateral DRGS. herefore, this time-dependent accumulation- of radiolabeled phosphatidylcholine in the ipsilateral DRGs is most likely due to retrograde axonal transport of locally-synthesized phospholipid material.