Rapid phase of axoplasmic flow and synaptic proteins: An electron microscopical autoradiographic study

Abstract

Abstract Electro microscopic autoradiography was used to study the distribution of labeled proteins in the pigeon optic tectum, 12 hours after intraocular injection of 3 H‐1‐leucine. More than 65% of the grains were detected over synaptic endings, in the fifth layer which is rich in retino‐tectal axon terminals. In the first layer which contains retino‐tectal fibers 70% of the grains were over axons. These data support the proposition that synaptic proteins migrate rapidly in the axon. Detailed examination showed that silver grains were predominatly located over the axolemma and agranular endoplasmic reticulum in axons, and over mitochondria and synaptic vesicles in neuronal endings.