AJP - Heart and Circulatory Physiology, Vol 272, Issue 5 2164-H2172, Copyright © 1997 by American Physiological Society

ARTICLES

Inhibition by external Cd2+ of Na/Ca exchange and L-type Ca channel in rabbit ventricular myocytes

I. A. Hobai, J. A. Bates, F. C. Howarth and A. J. Levi
Department of Physiology, School of Medical Sciences, University of Bristol, United Kingdom.

We investigated the effect of external Cd2+ on the Na/Ca exchange and the L-type Ca channel current (ICa,L) in whole cell patch-clamped rabbit ventricular myocytes at 36 degrees C. After the interfering ion channels and the Na/K pump were blocked, the exchange current was measured as the membrane current that was inhibited by 5 mM nickel. External Cd2+ inhibited Na/Ca exchange with a dissociation constant (KD) of 320.6 +/- 12.4 microM and a Hill coefficient of 1.5 +/- 0.09 (n = 13 cells) and ICa,L with a KD of 2.14 +/- 0.15 microM and a Hill coefficient of 0.74 +/- 0.03 (n = 11 cells). We observed some overlap in the Cd2+ concentration that blocked each mechanism. Cd2+ (100-500 microM) is used commonly to block ICa,L completely. However, 100 microM Cd2+ also inhibits 20% of the Na/Ca exchange activity, whereas 500 microM Cd2+ inhibits 60%.

This article has been cited by other articles:

				U. Kirchhefer, J. Klimas, H. A. Baba, I. B. Buchwalow, L. Fabritz, M. Huls, M. Matus, F. U. Muller, W. Schmitz, and J. Neumann Triadin is a critical determinant of cellular Ca cycling and contractility in the heart Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H3165 - H3174. [Abstract] [Full Text] [PDF]

				Z. Ren and C. M. Baumgarten Antagonistic regulation of swelling-activated Cl- current in rabbit ventricle by Src and EGFR protein tyrosine kinases Am J Physiol Heart Circ Physiol, June 1, 2005; 288(6): H2628 - H2636. [Abstract] [Full Text] [PDF]

				J. Bokenes, I. Sjaastad, and O. M. Sejersted Artifactual contractions triggered by field stimulation of cardiomyocytes J Appl Physiol, May 1, 2005; 98(5): 1712 - 1719. [Abstract] [Full Text] [PDF]

				A. Rocher, E. Geijo-Barrientos, A. I. Caceres, R. Rigual, C. Gonzalez, and L. Almaraz Role of voltage-dependent calcium channels in stimulus-secretion coupling in rabbit carotid body chemoreceptor cells J. Physiol., January 15, 2005; 562(2): 407 - 420. [Abstract] [Full Text] [PDF]

				K. H. Seul, J. H. Han, K. Y. Kang, S. Z. Kim, and S. H. Kim Regulation of ANP secretion by cardiac Na+/Ca2+ exchanger using a new controlled atrial model Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2003; 284(1): R31 - R40. [Abstract] [Full Text] [PDF]

				K. N. Jew, M. C. Olsson, E. A. Mokelke, B. M. Palmer, and R. L. Moore Endurance training alters outward K+ current characteristics in rat cardiocytes J Appl Physiol, April 1, 2001; 90(4): 1327 - 1333. [Abstract] [Full Text] [PDF]

				B. F. A. S. Sakmann, A. J. Spindler, S. M. Bryant, K. W. Linz, and D. Noble Distribution of a Persistent Sodium Current Across the Ventricular Wall in Guinea Pigs Circ. Res., November 10, 2000; 87(10): 910 - 914. [Abstract] [Full Text] [PDF]

				I. A. Hobai and B. O'Rourke Enhanced Ca2+-Activated Na+-Ca2+ Exchange Activity in Canine Pacing-Induced Heart Failure Circ. Res., October 13, 2000; 87(8): 690 - 698. [Abstract] [Full Text] [PDF]

				Y. Kusaka, R. A. Kelly, G. H. Williams, and I. Kifor Coronary microvascular endothelial cells cosecrete angiotensin II and endothelin-1 via a regulated pathway Am J Physiol Heart Circ Physiol, September 1, 2000; 279(3): H1087 - H1096. [Abstract] [Full Text] [PDF]

				J.-B. Shen, B. Jiang, and A. J. Pappano Comparison of L-Type Calcium Channel Blockade by Nifedipine and/or Cadmium in Guinea Pig Ventricular Myocytes J. Pharmacol. Exp. Ther., August 1, 2000; 294(2): 562 - 570. [Abstract] [Full Text]

				H. Sun, D. Chartier, S. Nattel, and N. Leblanc Ca2+-activated Cl- current can be triggered by Na+ current-induced SR Ca2+ release in rabbit ventricle Am J Physiol Heart Circ Physiol, October 1, 1999; 277(4): H1467 - H1477. [Abstract] [Full Text] [PDF]

				M. P. Blaustein and W. J. Lederer Sodium/Calcium Exchange: Its Physiological Implications Physiol Rev, July 1, 1999; 79(3): 763 - 854. [Abstract] [Full Text] [PDF]

				E. Carmeliet Cardiac Ionic Currents and Acute Ischemia: From Channels to Arrhythmias Physiol Rev, July 1, 1999; 79(3): 917 - 1017. [Abstract] [Full Text] [PDF]

				T. Saeki, J.-B. Shen, and A. J. Pappano Inositol-1,4,5-trisphosphate increases contractions but not L-type calcium current in guinea pig ventricular myocytes Cardiovasc Res, March 1, 1999; 41(3): 620 - 628. [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]