AJP - Heart Calcium Transients and Cell-Sarcomere
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Heart Circ Physiol 273: H2891-H2898, 1997;
0363-6135/97 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
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 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 Google Scholar
Google Scholar
Right arrow Articles by Mikane, T.
Right arrow Articles by Suga, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mikane, T.
Right arrow Articles by Suga, H.
Vol. 273, Issue 6, H2891-H2898, December 1997

MODELING IN PHYSIOLOGY
Mechanism of constant contractile efficiency under cooling inotropy of myocardium: simulation

Takeshi Mikane1, Junichi Araki1, Kunihisa Kohno1, Yasunori Nakayama1, Shunsuke Suzuki1, Juichiro Shimizu1, Hiromi Matsubara1, Masahisa Hirakawa2, Miyako Takaki3, and Hiroyuki Suga1

Departments of 1 Physiology II and 2 Anesthesiology and Resuscitology, Okayama University Medical School, Shikatacho, Okayama 700; and 3 Department of Physiology II, Nara Medical University, Shijocho, Kashihara 634, Japan

We have reported that, in canine hearts, cardiac cooling to 29°C enhanced left ventricular contractility but changed neither the contractile efficiency of cross-bridge (CB) cycling nor the excitation-contraction coupling energy. The mechanism of this intriguing energetics remained unknown. To get insights into this mechanism, we simulated myocardial cooling mechanoenergetics using basic Ca2+ and CB kinetics. We assumed that both adenosinetriphosphatase (ATPase)-dependent sarcoplasmic reticulum (SR) Ca2+ uptake and CB detachment decelerated with cooling. We also assumed that all the ATPase-independent SR Ca2+ release, Ca2+ binding to and dissociation from troponin, and CB attachment remained unchanged. The simulated cooling shifted the CB force-free Ca2+ concentration curve to a lower Ca2+ concentration, increasing the Ca2+ responsiveness of CB force generation, and increased the maximum Ca2+-activated force. The simulation most importantly showed that these cooling effects combined led to a constant contractile efficiency when Ca2+ uptake and CB detachment rate constants changed appropriately. This result seems to account for our experimentally observed constant contractile efficiency under cooling inotropy.

temperature; inotropism; contractility; energetics; responsiveness


This article has been cited by other articles:


Home page
 Am. J. Physiol. Cell Physiol.Home page
R. H. Shutt and S. E. Howlett
Hypothermia increases the gain of excitation-contraction coupling in guinea pig ventricular myocytes
Am J Physiol Cell Physiol, September 1, 2008; 295(3): C692 - C700.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
R. Lang, A. V. Gomes, J. Zhao, P. R. Housmans, T. Miller, and J. D. Potter
Functional Analysis of a Troponin I (R145G) Mutation Associated with Familial Hypertrophic Cardiomyopathy
J. Biol. Chem., March 29, 2002; 277(14): 11670 - 11678.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
J. Mizuno, J. Araki, S. Suzuki, S. Mohri, T. Mikane, J. Shimizu, H. Matsubara, M. Hirakawa, T. Ohe, and H. Suga
Temperature-dependent postextrasystolic potentiation and Ca2+ recirculation fraction in canine hearts
Am J Physiol Heart Circ Physiol, February 1, 2002; 282(2): H403 - H413.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
O. M. Hernandez, P. R. Housmans, and J. D. Potter
Plasticity in Skeletal, Cardiac, and Smooth Muscle: Invited Review: Pathophysiology of cardiac muscle contraction and relaxation as a result of alterations in thin filament regulation
J Appl Physiol, March 1, 2001; 90(3): 1125 - 1136.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
A. Saeki, Y. Goto, K. Hata, T. Takasago, T. Nishioka, and H. Suga
Negative inotropism of hyperthermia increases oxygen cost of contractility in canine hearts
Am J Physiol Heart Circ Physiol, December 1, 2000; 279(6): H2855 - H2864.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
T. Mikane, J. Araki, S. Suzuki, J. Mizuno, J. Shimizu, S. Mohri, H. Matsubara, M. Hirakawa, T. Ohe, and H. Suga
O2 cost of contractility but not of mechanical energy increases with temperature in canine left ventricle
Am J Physiol Heart Circ Physiol, July 1, 1999; 277(1): H65 - H73.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
B. C. Knollmann, S. A. Blatt, K. Horton, F. de Freitas, T. Miller, M. Bell, P. R. Housmans, N. J. Weissman, M. Morad, and J. D. Potter
Inotropic Stimulation Induces Cardiac Dysfunction in Transgenic Mice Expressing a Troponin T (I79N) Mutation Linked to Familial Hypertrophic Cardiomyopathy
J. Biol. Chem., March 23, 2001; 276(13): 10039 - 10048.
[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