Journal of Applied Physiology Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 88: 180-185, 2000;
8750-7587/00 $5.00
This Article
Right arrow Full Text Free
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (19)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Allen, K.
Right arrow Articles by Kerrick, W. G. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Allen, K.
Right arrow Articles by Kerrick, W. G. L.
Vol. 88, Issue 1, 180-185, January 2000

Ca2+ measurements in skinned cardiac fibers: effects of Mg2+ on Ca2+ activation of force and fiber ATPase

Keri Allen, Yuan Yuan Xu, and W. Glenn L. Kerrick

Department of Physiology and Biophysics, University of Miami School of Medicine, Miami, Florida 33101

In contrast to previous studies, a new fluorescent method was used to accurately determine the Ca2+ concentration in test solutions used to activate skinned rat cardiac cells. This method used the calcium green-2 fluorescent indicator, which is shown to change its fluorescence over the Ca2+ range responsible for Ca2+ activation of force and ATPase. The dissociation constant (Kd) of calcium green-2 for Ca2+ was determined for three different Mg2+ concentrations in solutions similar to those used in the experiment. Increasing Mg2+ concentration from 1.0 to 8.0 mM had no significant effect on the Ca2+ sensitivity of either force or actomyosin ATPase activity, in contrast to previous reported studies on force. The ATPase activity was activated at lower Ca2+ concentration than the force. The ratio (ATPase/force) is proportional to the dissociation rate of force-generating myosin cross bridges and decreased during Ca2+ activation. These findings are consistent with the hypothesis that cardiac muscle contraction is activated by a single Ca2+-specific binding site on troponin C.

calcium; magnesium; binding constant; dissociation constant; actomyosin


This article has been cited by other articles:


Home page
 FASEB J.Home page
W. G. L. Kerrick, K. Kazmierczak, Y. Xu, Y. Wang, and D. Szczesna-Cordary
Malignant familial hypertrophic cardiomyopathy D166V mutation in the ventricular myosin regulatory light chain causes profound effects in skinned and intact papillary muscle fibers from transgenic mice
FASEB J, March 1, 2009; 23(3): 855 - 865.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
Y. Wen, J. R. Pinto, A. V. Gomes, Y. Xu, Y. Wang, Y. Wang, J. D. Potter, and W. G. L. Kerrick
Functional Consequences of the Human Cardiac Troponin I Hypertrophic Cardiomyopathy Mutation R145G in Transgenic Mice
J. Biol. Chem., July 18, 2008; 283(29): 20484 - 20494.
[Abstract] [Full Text] [PDF]

Home page
 FASEB J.Home page
D. Szczesna-Cordary, M. Jones, J. R. Moore, J. Watt, W. G. L. Kerrick, Y. Xu, Y. Wang, C. Wagg, and G. D. Lopaschuk
Myosin regulatory light chain E22K mutation results in decreased cardiac intracellular calcium and force transients
FASEB J, December 1, 2007; 21(14): 3974 - 3985.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
O. M. Hernandez, D. Szczesna-Cordary, B. C. Knollmann, T. Miller, M. Bell, J. Zhao, S. G. Sirenko, Z. Diaz, G. Guzman, Y. Xu, et al.
F110I and R278C Troponin T Mutations That Cause Familial Hypertrophic Cardiomyopathy Affect Muscle Contraction in Transgenic Mice and Reconstituted Human Cardiac Fibers
J. Biol. Chem., November 4, 2005; 280(44): 37183 - 37194.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
S. B. Tikunova and J. P. Davis
Designing Calcium-sensitizing Mutations in the Regulatory Domain of Cardiac Troponin C
J. Biol. Chem., August 20, 2004; 279(34): 35341 - 35352.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
T. E. Gillis, C. D. Moyes, and G. F. Tibbits
Sequence mutations in teleost cardiac troponin C that are permissive of high Ca2+ affinity of site II
Am J Physiol Cell Physiol, May 1, 2003; 284(5): C1176 - C1184.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
D. A. Lowe, D. D. Thomas, and L. V. Thompson
Force generation, but not myosin ATPase activity, declines with age in rat muscle fibers
Am J Physiol Cell Physiol, July 1, 2002; 283(1): C187 - C192.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
Y. Wang and W. G. L. Kerrick
The off rate of Ca2+ from troponin C is regulated by force-generating cross bridges in skeletal muscle
J Appl Physiol, June 1, 2002; 92(6): 2409 - 2418.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
T. Miller, D. Szczesna, P. R. Housmans, J. Zhao, F. de Freitas, A. V. Gomes, L. Culbreath, J. McCue, Y. Wang, Y. Xu, et al.
Abnormal Contractile Function in Transgenic Mice Expressing a Familial Hypertrophic Cardiomyopathy-linked Troponin T (I79N) Mutation
J. Biol. Chem., February 2, 2001; 276(6): 3743 - 3755.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online