Localizations of aldehyde-resistant nucleoside phosphatase activities in frozen sections of rat cardiac muscle have been studied by electron microscopy. Activities are higher after fixation with formaldehyde than with glutaraldehyde. After incubation with adenosine triphosphate or inosine diphosphate at pH 7.2, reaction product is found in the "terminal cisternae" or "transverse sacs" of the sarcoplasmic reticulum, which, together with the "intermediary vesicles" (T system), constitute the "dyads" or "triads". Reaction product is also present at the membranes of micropinocytotic vacuoles which apparently form from the plasma membrane of capillary endothelial cells and from the sarcolemma. In certain regions of the intercalated discs, reaction product is found within the narrow spaces between sarcolemmas of adjacent cells and within micropinocytotic vacuoles that seem to form from the sarcolemma. With inosine diphosphate, reaction product is also found in other parts of the sarcoplasmic reticulum. After incubation with cytidine monophosphate at pH 5, reaction product is present in the transverse sacs of sarcoplasmic reticulum, in micropinocytotic vacuoles in capillary endothelium, and in lysosomes of muscle fibers and capillaries. The possible significance of the sarcoplasmic reticulum phosphatases is discussed in relation to the role the reticulum probably plays in moving calcium ions and thereby controlling contraction and relaxation of the muscle fiber.
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1 May 1965
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May 01 1965
NUCLEOSIDE PHOSPHATASE ACTIVITIES IN RAT CARDIAC MUSCLE
Edward Essner,
Edward Essner
From the Pathology Department, Albert Einstein College of Medicine, Yeshiva University, New York.
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Alex B. Novikoff,
Alex B. Novikoff
From the Pathology Department, Albert Einstein College of Medicine, Yeshiva University, New York.
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Nelson Quintana
Nelson Quintana
From the Pathology Department, Albert Einstein College of Medicine, Yeshiva University, New York.
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Edward Essner
From the Pathology Department, Albert Einstein College of Medicine, Yeshiva University, New York.
Alex B. Novikoff
From the Pathology Department, Albert Einstein College of Medicine, Yeshiva University, New York.
Nelson Quintana
From the Pathology Department, Albert Einstein College of Medicine, Yeshiva University, New York.
Dr. Essner's present address is Sloan-Kettering Institute for Cancer Research, Rye, New York
Received:
January 06 1964
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1965 by The Rockefeller Institute Press
1965
J Cell Biol (1965) 25 (2): 201–215.
Article history
Received:
January 06 1964
Citation
Edward Essner, Alex B. Novikoff, Nelson Quintana; NUCLEOSIDE PHOSPHATASE ACTIVITIES IN RAT CARDIAC MUSCLE . J Cell Biol 1 May 1965; 25 (2): 201–215. doi: https://doi.org/10.1083/jcb.25.2.201
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