title: Rapid transport of phosphatidylcholine occurring simultaneously with protein transport in the frog sciatic nerve.
abstract: 1. Either l-[4,5-(3)H]leucine or [Me-(3)H]choline, or both l-[U-(14)C]leucine and [Me-(3)H]-choline, were injected into the ninth dorsal root ganglion of the frog, and peripheral transport of labelled proteins and/or phospholipids, mostly phosphatidylcholine, was studied by analysis of consecutive segments of the sciatic nerve. 2. At 25 degrees C, approx. 5% of the (3)H-labelled protein was transported at the rate of 152mm/day. The rate was temperature-dependent with the Q(10) value of 2.6. The flow was completely blocked by the local application of colchicine, but was unaffected by cytochalasin D. 3. [Me-(3)H]-Choline was incorporated into phosphatidylcholine at a comparatively slow rate, but was transported in the nerve at a rate equivalent to that for (3)H-labelled proteins. 4. The simultaneous transport of phosphatidylcholine and the protein was further supported in the double-labelling experiments by an identical transport rate of (3)H-labelled phosphatidylcholine and (14)C-labelled proteins, by their identical temperature dependence, by simultaneous blockade with colchicine, and also by the parallel distribution of the two labels in subcellular fractions. Specific radioactivities on a protein basis of both (3)H and (14)C labels were highest in microsomal subfractions enriched with Na(+)-plus-K(+)-stimulated adenosine triphosphatase and acetylcholinesterase. It is suggested that (3)H-labelled phosphatidylcholine and (14)C-labelled proteins transported in the nerve reside in the same structural entity, most probably a membrane component.
mesh_terms: D000110:Acetylcholinesterase; D000251:Adenosine Triphosphatases; D000818:Animals; D001001:Anura; D001369:Axons / Q000378:metabolism; D001693:Biological Transport, Active / Q000187:drug effects; D002250:Carbon Radioisotopes; D002794:Choline / Q000378:metabolism; D003078:Colchicine / Q000494:pharmacology; D003572:Cytochalasins / Q000494:pharmacology; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism*; D011188:Potassium; D011892:Rana catesbeiana; D012584:Sciatic Nerve / Q000378:metabolism*; D012964:Sodium; D013696:Temperature; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D003572:Cytochalasins; D009419:Nerve Tissue Proteins; D010713:Phosphatidylcholines; D014316:Tritium; D012964:Sodium; D000110:Acetylcholinesterase; D000251:Adenosine Triphosphatases; D007930:Leucine; D002794:Choline; D011188:Potassium; D003078:Colchicine