HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Costantin, L. L. Search for Related Content PubMed PubMed Citation Articles by Costantin, L. L.

1. The effect of extracellular calcium and magnesium on the contraction threshold and on the thresholds for an increase in sodium and potassium conductance with depolarization was studied in voltage-clamped frog muscle fibres.

2. A larger depolarization was required to reach each of the three thresholds when the concentration of divalent cation was increased.

3. The contraction and potassium conductance thresholds appeared to shift in parallel with alterations in calcium over the concentration range 0·2-10·0 mM and in magnesium over the concentration range 5·4-90·0 mM. The shift amounted to about 4 mV for a threefold change in concentration of divalent cation.

4. The sodium conductance threshold was much more sensitive to alterations in divalent cation concentration than was either the contraction or the potassium conductance threshold.

This article has been cited by other articles:

				S. P. Cairns, W. A. Hing, J. R. Slack, R. G. Mills, and D. S. Loiselle Role of extracellular [Ca2+] in fatigue of isolated mammalian skeletal muscle J Appl Physiol, April 1, 1998; 84(4): 1395 - 1406. [Abstract] [Full Text] [PDF]