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Dextrans as markers for endocytosis in innervated and denervated skeletal muscle
Author(s) -
Elmquist Stefan,
Libelius Rolf,
Lawoko Grace,
Tågerud Sven
Publication year - 1992
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880150803
Subject(s) - endocytosis , skeletal muscle , biology , anatomy , endocrinology , medicine , microbiology and biotechnology , neuroscience , receptor
Abstract Fluorescence‐labeled dextrans were evaluated as markers for endocytosis in skeletal muscle. Fluorescein isothiocyanate (FITC)‐labeled dextrans (average molecular weight 3900 to 71200) showed a higher uptake in denervated than in innervated muscle both in vitro and in vivo. The in vitro uptake of FITC‐dextran (35.600) increased linearly with time at 37°C, and was almost completely inhibited by low temperature (4°C). The uptake was not a pure bulk uptake, because a saturable component was evident from the concentration dependence and from competition experiments with unlabeled dextran. The uptake of FITC‐labeled or rhodamine B isothiocyanate (RITC)‐labeled dextrans in denervated muscle occurred mainly in small segments of the fibers centered around the denervated endplate region. However, not all denervated fibers showed such segments. Periodic acid Schiff's base staining for carbohydrates stained dextrans in denervated muscle fibers. Some staining, probably of lysosomes, was also observed in denervated muscle not exposed to dextran. © 1992 John Wiley & Sons, Inc.