DISTRIBUTION OF LEUCINE-3H DURING AXOPLASMIC TRANSPORT WITHIN REGENERATING NEURONS AS DETERMINED BY ELECTRON-MICROSCOPE RADIOAUTOGRAPHY

摘要: The distribution of leucine-3H in neurons was determined by electron-microscope radioautography after infusion label into the spinal cord or sensory ganglia regenerating newts. In nerve cell bodies 3 days infusion, highest concentration per unit area occurred over rough-surfaced endoplasmic reticulum. large brachial nerves, silver grains were not distributed uniformly axoplasm, indicating that labeled materials are restricted their movement to certain regions axon. Almost all radioautographic observed myelinated nerves could be accounted for presence a band occupying 1500–9000 A inside axolemma. This region axon rich microtubules and organelles while unlabeled central core contained mainly neurofilaments. observation supports hypothesis related axonal transport. small, vesicle-filled terminals blastema, material thin zone short distance beneath plasma membrane terminal largely unlabeled. peripheral pattern labeling endings is consistent with successive addition newly synthesized proteins at periphery growth cone release substances such as trophic factors terminal.