期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：21
页码：6707-6711
DOI：10.1073/pnas.79.21.6707
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The tetrodotoxin binding protein, a major component of the Na+ channel, has been purified from the electric organ of the South American eel Electrophorus electricus. Antibodies to this protein were raised in rabbits and their specificity was demonstrated by a highly sensitive radioimmunoassay and by immunoprecipitation procedures. These antibodies were used to examine the distribution of the binding protein in the eel electroplax membranes and along myelinated nerve axons. The distribution of the antigen was determined by using the peroxidase-antiperoxidase technique at both the light and electron microscopic levels. In the electrocytes of the electric organ, only the innervated face showed staining in experimental material. The stained regions of electroplax plasmalemma included the caveolae of the innervated surface while caveolae of the non-innervated surface did not stain. Thus, the innervated surface including caveolae exclusively contains the Na+ channels. Along myelinated axons, staining was limited to the nodal zone of the node of Ranvier. The paranodal and internodal zones did not stain for the binding protein. Limited diffusion of primary IgG and subsequent reactants into the paranodal and internodal sites was eliminated as a possible source of focal staining at nodes because mechanically demyelinated preparations also exhibited focal nodal staining. Thus, this tetrodotoxin binding protein component of the Na+ channel is located solely within the nodal zone of the node of Ranvier.
