Early effects of carbachol on the morphology of motor endplates of mammalian skeletal muscle fibers

Voigt, T (2010). Early effects of carbachol on the morphology of motor endplates of mammalian skeletal muscle fibers. Muscle & nerve, 41(3), pp. 399-405. New York, N.Y.: John Wiley & Sons 10.1002/mus.21508

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Long-term disturbance of the calcium homeostasis of motor endplates (MEPs) causes necrosis of muscle fibers. The onset of morphological changes in response to this disturbance, particularly in relation to the fiber type, is presently unknown. Omohyoid muscles of mice were incubated for 1-30 minutes in 0.1 mM carbachol, an acetylcholine agonist that causes an inward calcium current. In these muscles, the structural changes of the sarcomeres and the MEP sarcoplasm were evaluated at the light- and electron-microscopic level. Predominantly in type I fibers, carbachol incubation resulted in strong contractures of the sarcomeres underlying the MEPs. Owing to these contractures, the usual beret-like form of the MEP-associated sarcoplasm was deformed into a mushroom-like body. Consequently, the squeezed MEPs partially overlapped the adjacent muscle fiber segments. There are no signs of contractures below the MEPs if muscles were incubated in carbachol in calcium-free Tyrode's solution. Carbachol induced inward calcium current and produced fiber-type-specific contractures. This finding points to differences in the handling of calcium in MEPs. Possible mechanisms for these fiber-type-specific differences caused by carbachol-induced calcium entry are assessed.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy

UniBE Contributor:

Voigt, Tilman

ISSN:

0148-639X

Publisher:

John Wiley & Sons

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:07

Last Modified:

06 Dec 2013 13:19

Publisher DOI:

10.1002/mus.21508

Web of Science ID:

000275139700017

URI:

https://boris.unibe.ch/id/eprint/183 (FactScience: 196705)

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