Abstract
Ramsey and Street1, working on single muscle fibres, concluded that relaxation in skeletal muscle was active. Prof. A. V. Hill2 has conclusively shown that relaxation in skeletal muscle is passive. We stimulated the frog's rectus abdominis with potassium salts and acetylcholine and did not find any active relaxation. In unstriated muscle relaxation is active under some conditions and passive under others3–5. In unstriated muscle there would appear to be two cycles: in one, the energy for contraction is derived from chemical stores; in the other, the energy for contraction is derived from energy previously stored in the structure. Striated muscle appears to possess the former cycle only. This, we think, is the fundamental difference between the two kinds of muscle.
Similar content being viewed by others
Article PDF
References
Ramsey, R. W., and Street, S. F., J. Cell. Comp. Physiol., 15, 11 (1940).
Hill, A. V., Proc. Roy. Soc., B, 136, 420 (1949).
Singh, S. I., and Singh, I., Curr. Sci., 17, 306 (1948).
Singh, S. I., and Singh, I., Proc. Ind. Acad. Sci., B, 30, 343 (1948).
Singh, S. I., and Singh, I., Curr. Sci., 19, 60 (1950).
Rao, M. S., and Singh, I., J. Physiol., 98, 12 (1940).
Bharadwaj, U. R., and Singh, I. (unpublished observations).
Singh, S. I., and Singh, I., Proc. Ind. Acad. Sci., B, 27, 127 (1948).
Singh, I., Proc. Ind. Acad. Sci., B, 29, 190 (1949).
Singh, S. I., and Singh, I., Proc. Ind. Acad. Sci., B, 32, 12 (1950).
Burn, J. H., and Vane, J. R., J. Physiol., 108, 104 (1949).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
SINGH, S., SINGH, I. Active Relaxation of Unstriated Muscle. Nature 166, 647 (1950). https://doi.org/10.1038/166647a0
Issue date:
DOI: https://doi.org/10.1038/166647a0
This article is cited by
-
Adenosine Triphosphate and Muscular Contraction and Relaxation
Nature (1965)
-
Effect of Dinitrophenol on Active Relaxation of Unstriated Muscle
Nature (1962)
-
Absence of secretion of acetylcholine on stimulation of nerves in an unstriated muscle
Proceedings / Indian Academy of Sciences (1959)
-
Ionic changes in unstriated muscle immersed in sodium-free solutions
Proceedings / Indian Academy of Sciences (1957)
-
Muscular contraction and relaxation
Proceedings / Indian Academy of Sciences (1956)
