Volume 15, Issue 8 pp. 876-884
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Dextrans as markers for endocytosis in innervated and denervated skeletal muscle

Dr. Stefan Elmquist

Dr. Stefan Elmquist

Department of Pharmacology, University of Lund, Sweden

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Dr. Rolf Libelius

Dr. Rolf Libelius

Department of Clinical Neurophysiology, University of Umeå, Sweden

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Dr. Grace Lawoko

Dr. Grace Lawoko

Department of Pharmacology, University of Lund, Sweden

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Dr. Sven Tågerud

Corresponding Author

Dr. Sven Tågerud

Department of Pharmacology, University of Lund, Sweden

Department of Pharmacology, Sölvegatan 10, S-223 62 Lund, SwedenSearch for more papers by this author
First published: August 1992
Citations: 15

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.

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