¹ From the Department of Physiology, The University of Rochester School of Medicine and Dentistry, Rochester, New York

1. A study of the calcium equilibrium in isolated frog muscle has been attempted.

2. When sartorius muscles were immersed in Ca⁴⁵ Ringer's solution, the surface phase took up the Ca⁴⁵ in about 1 minute; the extracellular water space and connective tissue in about 30 minutes; and the intracellular space in about 300 minutes.

3. The percentages of total calcium in the whole muscle immersed in Ringer's solution was as follows: 10 per cent in the surface phase; 12 per cent in the extracellular water space; 17 per cent in the dry connective tissue; 24 per cent in the intracellular space; and 37 per cent as non-exchangeable calcium.

4. The exchange constants of isolated frog sartorius muscle to calcium has been determined. The flux of intracellular calcium in the steady state was approximately 0.8 mM/(liter hr).

5. It appears that there is a calcium pump pushing calcium out of the cell against an electrochemical gradient of about 4 cal./mM of calcium. However, since the flux is low, the maximum energy required per hour to pump calcium out of the cell against this high gradient is only about 2 cal./kg. muscle or about 1 per cent of the resting energy.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				L. L. Costantin, C. Franzini-Armstrong, and R. J. Podolsky Localization of Calcium-Accumulating Structures in Striated Muscle Fibers Science, January 8, 1965; 147(3654): 158 - 160. [Abstract] [PDF]

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents