The fine structure of desmosomes and intercalated discs in the toad heart is discussed. A definite relationship between the dense components of these structures and the dense region of the Z band is demonstrated. The dense region of the Z band characteristically widens at its approach to the plasma membrane, and often terminates beneath it in a distinct discoidal plaque. Cardiac desmosomes appear to be structures which result from the intimate apposition of plaques of Z band material. These desmosomes retain the Z band function as sites of attachment for myofilaments. The suggestion is made that rotation of a desmosome through 90° and splitting of filaments from the adjacent sarcomere could result in the formation of a simple step-like intercalated disc. Intermediate stages in this process are illustrated. Complex discs present in the toad probably represent the alignment of groups of simple discs produced by contractile forces. Possible physiologic functions of the disc and desmosome are discussed. Other morphologic features of toad cardiac cells include a distinct amorphous outer coat to the sarcolemma, a prominent N band, and a granular sarcoplasm with poorly developed reticulum.
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1 October 1960
Content prior to 1962 was published under the journal name
The Journal of Biophysical and Biochemical Cytology
Article|
October 01 1960
THE ULTRASTRUCTURE OF CARDIAC DESMOSOMES IN THE TOAD AND THEIR RELATIONSHIP TO THE INTERCALATED DISC
Philip M. Grimley,
Philip M. Grimley
From The Division of Laboratories and Research, New York State Department of Health, Albany
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George A. Edwards
George A. Edwards
From The Division of Laboratories and Research, New York State Department of Health, Albany
Search for other works by this author on:
Philip M. Grimley
From The Division of Laboratories and Research, New York State Department of Health, Albany
George A. Edwards
From The Division of Laboratories and Research, New York State Department of Health, Albany
Received:
August 12 1959
Copyright 1961 by The Rockefeller Institute Press
1960
J Biophys and Biochem Cytol (1960) 8 (2): 305–318.
Article history
Received:
August 12 1959
Citation
Philip M. Grimley, George A. Edwards; THE ULTRASTRUCTURE OF CARDIAC DESMOSOMES IN THE TOAD AND THEIR RELATIONSHIP TO THE INTERCALATED DISC . J Biophys and Biochem Cytol 1 October 1960; 8 (2): 305–318. doi: https://doi.org/10.1083/jcb.8.2.305
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