|
|
||||||||
Departments of Physiology and Cardio-Thoracic Surgery, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
Defects in myocyte contraction and relaxation are
key features of human heart failure. Sodium/calcium exchanger-mediated
contribution to contraction and relaxation were separated from other
mechanisms [L-type calcium current, sarco(endo)plasmic reticulum
(SR)
Ca2+-ATPase]
based on voltage, temperature, and selective blockers. Rod-shaped left
ventricular myocytes were isolated from failed human explants
(n = 29) via perfusion with
collagenase-containing Krebs solution. Action potentials using
perforated patch and contractions using an edge detector were recorded
at 0.5-1.5 Hz in Tyrode solution at 25°C and 37°C.
Contraction duration was dependent on action potential (AP) duration at
37°C but not at 25°C, suggesting the role of the exchanger in
relaxation and linking myocyte relaxation to the repolarization phase
of the AP. Voltage-clamp experiments from
50 to +10 mV for 1,500 ms in Tyrode or Na+- and
K+-free solutions after
conditioning pulses triggered biphasic contractions that included a
rapid SR-mediated component and a slower voltage-dependent exchanger-mediated component. We used thapsigargin to
block the SR, which eliminated the rapid component, and we used an
exchanger blocker, Kanebo 7943, which eliminated the slow
component. The exchanger was shown to contribute to
contraction through reverse-mode exchange, as well as to play a key
role in relaxation of human ventricular myocytes.
human myocytes; heart failure; sodium/calcium exchange; excitation-contraction coupling
This article has been cited by other articles:
![]() |
J. A. Wasserstrom and G. L. Aistrup Digitalis: new actions for an old drug Am J Physiol Heart Circ Physiol, November 1, 2005; 289(5): H1781 - H1793. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Song, X.-Q. Zhang, J. Wang, L. L. Carl, B. A. Ahlers, L. I. Rothblum, and J. Y. Cheung Sprint training improves contractility in postinfarction rat myocytes: role of Na+/Ca2+ exchange J Appl Physiol, August 1, 2004; 97(2): 484 - 490. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. L. De Jongh, V. Ramanathan, B. K. Hoffmeister, and R. A. Malkin Left ventricular geometry immediately following defibrillation: shock-induced relaxation Am J Physiol Heart Circ Physiol, March 1, 2003; 284(3): H815 - H819. [Abstract] [Full Text] [PDF] |
||||
![]() |
X.-Q. Zhang, J. Song, A. Qureshi, L. I. Rothblum, L. L. Carl, Q. Tian, and J. Y. Cheung Rescue of contractile abnormalities by Na+/Ca2+ exchanger overexpression in postinfarction rat myocytes J Appl Physiol, December 1, 2002; 93(6): 1925 - 1931. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Shenoy, I. Klein, and K. Ojamaa Differential regulation of SR calcium transporters by thyroid hormone in rat atria and ventricles Am J Physiol Heart Circ Physiol, October 1, 2001; 281(4): H1690 - H1696. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. L. Elias, A. Lukas, S. Shurraw, J. Scott, A. Omelchenko, G. J. Gross, M. Hnatowich, and L. V. Hryshko Inhibition of Na+/Ca2+ exchange by KB-R7943: transport mode selectivity and antiarrhythmic consequences Am J Physiol Heart Circ Physiol, September 1, 2001; 281(3): H1334 - H1345. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. H. Barry Na+-Ca2+ Exchange in Failing Myocardium : Friend or Foe? Circ. Res., September 29, 2000; 87(7): 529 - 531. [Full Text] [PDF] |
||||
![]() |
L.-Q. Zhang, X.-Q. Zhang, T. I. Musch, R. L. Moore, and J. Y. Cheung Sprint training restores normal contractility in postinfarction rat myocytes J Appl Physiol, September 1, 2000; 89(3): 1099 - 1105. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. M. Bers Calcium Fluxes Involved in Control of Cardiac Myocyte Contraction Circ. Res., August 18, 2000; 87(4): 275 - 281. [Full Text] [PDF] |
||||
![]() |
J. A. Wasserstrom, E. Holt, I. Sjaastad, P. K. Lunde, A. Odegaard, and O. M. Sejersted Altered E-C coupling in rat ventricular myocytes from failing hearts 6 wk after MI Am J Physiol Heart Circ Physiol, August 1, 2000; 279(2): H798 - H807. [Abstract] [Full Text] [PDF] |
||||
![]() |
L.-Q. Zhang, X.-Q. Zhang, Y.-C. Ng, L. I. Rothblum, T. I. Musch, R. L. Moore, and J. Y. Cheung Sprint training normalizes Ca2+ transients and SR function in postinfarction rat myocytes J Appl Physiol, July 1, 2000; 89(1): 38 - 46. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Wang, B. Nolan, W. Kutschke, and J. A. Hill Na+-Ca2+ Exchanger Remodeling in Pressure Overload Cardiac Hypertrophy J. Biol. Chem., May 18, 2001; 276(21): 17706 - 17711. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |