Proximo-Distal Movement of Phospholipid in the Axoplasm of the Intact and Regenerating Neurons

There is a considerable degree of certainty that most of the labeled phospholipids of the hypoglossal and vagal nerves are present inside the axon and that in intact nerves, the Schwann cells and the connective tissue cells of the peri- and endoneurium synthesize negligible amounts of 32 P-lipids.

Abstract

There is a considerable degree of certainty that most of the labeled phospholipids of the hypoglossal and vagal nerves are present inside the axon. Two groups of experiments substantiate this concept: the first has shown that in the distal part of the crushed nerves, labeled phospholipids are present in the newly regenerating axons; the second one has indicated that in intact nerves, the Schwann cells and the connective tissue cells of the peri- and endoneurium synthesize negligible amounts of 32P-lipids as the cells are only supplied with negligible amounts of 32P either by the blood and lymphatic vessels or by the endoneural space. A series of experiments presented in the chapter reveal various facts: (1) labeled phospholipids flow for long down the axon, (2) the flow per hour becomes constant after four days from labeling the bulb, and (3) labeled phospholipids are continuously synthesized within the confines of the bulb and then conveyed down the axon.