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Intracellular Ca 2+ channel immunoreactivity in neuroendocrine axon terminals
Author(s) -
Fisher Thomas E,
Carrion-Vazquez Mariano,
Fernandez Julio M
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)02043-3
Subject(s) - immunogold labelling , immunofluorescence , axon , cytoplasm , intracellular , microbiology and biotechnology , biology , biophysics , immunocytochemistry , chemistry , endocrinology , ultrastructure , anatomy , antibody , immunology
The concentration of neuroendocrine terminals in the neurohypophysis facilitates the identification and localization of Ca 2+ channel subtypes near neuroendocrine release sites. Immunoblots of rat neurohypophysial tissue identified the α 1 1.3, α 1 2.1, α 1 2.2, and α 1 2.3 Ca 2+ channel subunits. Immunofluorescence staining of axon terminal plasma membranes was weak, suggesting that Ca 2+ channels are dispersed. This contrasts with the highly punctate α 1 2.2 immunoreactivity in bovine chromaffin cells; the neurohypophysial terminals may therefore lack the specialized release zones found in those cells. Immunofluorescence and immunogold labeling identify dense core granule‐like structures in the terminal cytoplasm containing multiple Ca 2+ channel types. Ca 2+ channels in internal membranes may play an important role in channel targeting and distribution in neuroendocrine cells.