Density and distribution of α-bungarotoxin-binding sites in postsynaptic structures of regenerated rat skeletal muscle
Open Access
- 1 February 1981
- journal article
- research article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 88 (2), 338-345
- https://doi.org/10.1083/jcb.88.2.338
Abstract
Acetylcholine receptors (AChR) are organized in a discrete and predictable fashion in the postsynaptic regions of vertebrate skeletal muscle. When muscle is damaged, nerves and myofibers including muscular elements of the endplate degenerate, but the connective tissue elements survive. Muscle fibers regenerate within the basal lamina of the original myofiber. Postsynaptic differentiation in regenerated mammalian skeletal muscle can occur in different ways: at the site of the original endplate in the presence or absence of the nerve, or at ectopic regions of the regenerated myofiber in the presence of the nerve when the original endplate is not present. 125I-.alpha.-bungarotoxin (125I-.alpha.-BuTX) and EM autoradiography were used to examine the density and distribution of AChR in postsynaptic structures regenerated at the site of the original endplate in the absence of the nerve and at ectopic sites of the myofiber in the presence of the nerve when the original endplate was removed. In regenerated myofibers, the density of .alpha.-BuTX-binding sites fell within the range of densities observed in uninjured muscle whether postsynaptic differentiation occurred at the site of the original endplate in the absence of the nerve or at an originally ectopic position of the regenerated myofiber. In addition, the distribution of .alpha.-BuTX-binding sites within the regenerated postsynaptic regions closely resembled the distribution of .alpha.-BuTX-binding sites in uninjured muscle. Morphometric analysis was performed on postsynaptic structures formed at the site of the original endplate in the absence of the nerve or at an ectopic position of the regenerated myofiber by interaction of the nerve and muscle. Although variation in the depth of the primary cleft occurred, there was little difference between the overall structure of regenerated postsynaptic structures and that of endplates of uninjured muscles.This publication has 34 references indexed in Scilit:
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