|
|
||||||||
AJP - Cell Physiology, Vol 262, Issue 2 C316-C327, Copyright © 1992 by American Physiological Society
ARTICLES |
K. W. Spitzer and J. H. Bridge
Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City 84112.
Simultaneous measurements of intracellular pH (pHi) and tension development were made in resting cat papillary muscles and resting ventricular myocytes (cat, guinea pig). pH microelectrodes and the fluorescent indicator carboxy-seminaphthorhodafluor-1 (SNARF-1) were used to measure pHi in muscles and myocytes, respectively. pHi-induced changes in isometric muscle tension and myocyte length were elicited by variations in PCO2, HCO3-, and [NH4Cl]. Increased pHi elevated resting tension and decreased resting cell length, whereas decreased pHi decreased tension and increased cell length. The tension-pHi and cell length-pHi relationships were nonlinear and displayed hysteresis. A reduction in extracellular [Ca2+] from 2.7 to 0.5 mM caused little or no change in the tension and cell length responses to elevated pHi. Ca2+ uptake and/or release by the sarcoplasmic reticulum (SR) does not appear to be involved in the tension response to intracellular alkalosis because the response was unaffected by a postpacing rest period and was not inhibited by ryanodine (5 microM), which depletes SR Ca2+ stores. The cross-bridge inhibitor 2,3-butanedione monoxime (15 mM), but not internal dialysis with 14 mM ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetic acid, inhibited myocyte contractures elicited by elevated pHi. The latter finding suggests that factors other than pHi-induced increase in myofilament Ca2+ sensitivity may contribute to the resting contractile response to elevated pHi.
This article has been cited by other articles:
![]() |
C. S. Cox Jr, S. J. Allen, H. Sauer, and G. A. Laine Improved Myocardial Function Using a Na+/H+ Exchanger Inhibitor During Cardioplegic Arrest and Cardiopulmonary Bypass Chest, January 1, 2003; 123(1): 187 - 194. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Hendrikx, F. Rega, L. Jamaer, T. Valkenborgh, H. Gutermann, and U. Mees Na+/H+-exchange inhibition and aprotinin administration: promising tools for myocardial protection during minimally invasive CABG Eur. J. Cardiothorac. Surg., May 1, 2001; 19(5): 633 - 639. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. W. Spitzer, P. R. Ershler, R. L. Skolnick, and R. D. Vaughan-Jones Generation of intracellular pH gradients in single cardiac myocytes with a microperfusion system Am J Physiol Heart Circ Physiol, April 1, 2000; 278(4): H1371 - H1382. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Ito, Y. Kagaya, T. Ishizuka, N. Ito, N. Ishide, and K. Shirato Diacylglycerol delays pHi overshoot after reperfusion and attenuates contracture in isolated, paced myocytes Am J Physiol Heart Circ Physiol, November 1, 1999; 277(5): H1708 - H1717. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Tajima, J. Bartunek, E. O. Weinberg, N. Ito, and B. H. Lorell Atrial Natriuretic Peptide Has Different Effects on Contractility and Intracellular pH in Normal and Hypertrophied Myocytes From Pressure-Overloaded Hearts Circulation, December 15, 1998; 98(24): 2760 - 2764. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. J. Muller-Borer, H. Yang, S. A. M. Marzouk, J. J. Lemasters, and W. E. Cascio pHi and pHo at different depths in perfused myocardium measured by confocal fluorescence microscopy Am J Physiol Heart Circ Physiol, December 1, 1998; 275(6): H1937 - H1947. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. L. Skolnick, S. E. Litwin, W. H. Barry, and K. W. Spitzer Effect of ANG II on pHi, [Ca2+]i, and contraction in rabbit ventricular myocytes from infarcted hearts Am J Physiol Heart Circ Physiol, November 1, 1998; 275(5): H1788 - H1797. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. R. Boston, T. Koyama, J. Rodriguez-Larrain, A. Zou, Z. Su, and W. H. Barry Effects of Angiotensin II on Intracellular Calcium and Contracture in Metabolically Inhibited Cardiomyocytes J. Pharmacol. Exp. Ther., May 1, 1998; 285(2): 716 - 723. [Abstract] [Full Text] |
||||
![]() |
L. Vittone, C. Mundina-Weilenmann, M. Said, and A. Mattiazzi Mechanisms Involved in the Acidosis Enhancement of the Isoproterenol-induced Phosphorylation of Phospholamban in the Intact Heart J. Biol. Chem., April 17, 1998; 273(16): 9804 - 9811. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |