| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
We tested the hypothesis that both stretch-activated channels (SACs) and intracellular calcium ([Ca2+]i) are important in the electrical response of single guinea-pig ventricular myocytes to axial stretch. Myocytes were attached to carbon fibre transducers and stretched, sarcomere length increased by approximately 9 %, and there was a prolongation of the action potential duration. Streptomycin, a blocker of SACs, had no effect upon the shortening, [Ca2+]i transients or action potentials of electrically stimulated, unstretched myocytes, at a concentration of 50 µM, but at 40 µM, prevented any stretch-induced increase in action potential duration. Under action potential clamp, stretch elicited a current with a linear current-voltage relationship that was inward at membrane potentials negative to its reversal potential of -30 mV, in 10 of 24 cells tested, and was consistent with the activation of non-specific, cationic SACs. This current was not seen in any stretched cells that were exposed to 40 µM streptomycin. However, exposure of cells to 5 µM BAPTA-AM, in order to reduce [Ca2+]i transients, also abolished stretch-induced prolongation of the action potential. We conclude that both SACs and [Ca2+]i are important in the electrical response of cardiac myocytes to stretch, and propose that stretch-induced changes in electrical activity and [Ca2+]i may be linked by inter-dependent mechanisms.
This article has been cited by other articles:
|
|
 |
|
  J. P. Fahrenbach, R. Mejia-Alvarez, and K. Banach The relevance of non-excitable cells for cardiac pacemaker function J. Physiol., December 1, 2007; 585(2): 565 - 578. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Bupha-Intr, J. W. Holmes, and P. M. L. Janssen Induction of hypertrophy in vitro by mechanical loading in adult rabbit myocardium Am J Physiol Heart Circ Physiol, December 1, 2007; 293(6): H3759 - H3767. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Lu, C. Jun-xian, X. Rong-sheng, L. Jia, H. Ying, Z. Li-qun, and D. Ying-nan The effect of streptomycin on stretch-induced electrophysiological changes of isolated acute myocardial infarcted hearts in rats Europace, August 1, 2007; 9(8): 578 - 584. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A. Niederer and N. P. Smith A Mathematical Model of the Slow Force Response to Stretch in Rat Ventricular Myocytes Biophys. J., June 1, 2007; 92(11): 4030 - 4044. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. E. D. J. ter Keurs and P. A. Boyden Calcium and Arrhythmogenesis Physiol Rev, April 1, 2007; 87(2): 457 - 506. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. J. COOPER and P. KOHL Species- and Preparation-Dependence of Stretch Effects on Sino-Atrial Node Pacemaking Ann. N.Y. Acad. Sci., June 1, 2005; 1047(1): 324 - 335. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Calaghan and E. White Activation of Na+-H+ exchange and stretch-activated channels underlies the slow inotropic response to stretch in myocytes and muscle from the rat heart J. Physiol., August 15, 2004; 559(1): 205 - 214. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. LAMMERDING, R. D. KAMM, and R. T. LEE Mechanotransduction in Cardiac Myocytes Ann. N.Y. Acad. Sci., May 1, 2004; 1015(1): 53 - 70. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Kohl Heterogeneous Cell Coupling in the Heart: An Electrophysiological Role for Fibroblasts Circ. Res., September 5, 2003; 93(5): 381 - 383. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
