AJP - Heart and Circulatory Physiology, Vol 253, Issue 5 1018-H1025, Copyright © 1987 by American Physiological Society

ARTICLES

Electrical restitution process in dispersed canine cardiac Purkinje and ventricular cells

R. B. Robinson, P. A. Boyden, B. F. Hoffman and K. W. Hewett
Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, New York 10032.

Rate-dependent changes in cardiac action potential duration (APD) have been related to ion accumulation and depletion in restricted extracellular spaces. Isolated cardiac cells lack intercellular clefts and thus are less likely than intact tissue to experience ionic transients immediately outside the plasma membrane. Furthermore, isolated Purkinje cells lack the T tubules found in ventricular tissue and cells, which also can be a site of ion accumulation and depletion. We therefore employed single canine ventricular and Purkinje cells to investigate the contribution of restricted spaces to the electrical restitution process. In both cell types, abrupt changes in cycle length do not alter resting potential, but APD alters with a time constant of approximately 1 min. In addition, both preparations exhibit two components to the electrical restitution process of the APD. The rapid component has a time constant of 66 +/- 17 ms in the ventricle cells and 186 +/- 43 ms in the Purkinje cells. The slower component is both smaller and more variable. These values are similar to those reported in intact canine ventricular and Purkinje tissue. Thus the restitution process of APD, as measured in these isolated cardiac cells, is not markedly dependent on the presence or absence of restricted extracellular spaces.

This article has been cited by other articles:

				D. J. Dosdall, P. B. Tabereaux, J. J. Kim, G. P. Walcott, J. M. Rogers, C. R. Killingsworth, J. Huang, P. G. Robertson, W. M. Smith, and R. E. Ideker Chemical ablation of the Purkinje system causes early termination and activation rate slowing of long-duration ventricular fibrillation in dogs Am J Physiol Heart Circ Physiol, August 1, 2008; 295(2): H883 - H889. [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]

				A. M. Pitruzzello, W. Krassowska, and S. F. Idriss Spatial heterogeneity of the restitution portrait in rabbit epicardium Am J Physiol Heart Circ Physiol, March 1, 2007; 292(3): H1568 - H1578. [Abstract] [Full Text] [PDF]

				Z. Qu Dynamical effects of diffusive cell coupling on cardiac excitation and propagation: a simulation study Am J Physiol Heart Circ Physiol, December 1, 2004; 287(6): H2803 - H2812. [Abstract] [Full Text] [PDF]

				P. A. Boyden, J. Pu, J. Pinto, and H. E. D. J. t. Keurs Ca2+ Transients and Ca2+ Waves in Purkinje Cells : Role in Action Potential Initiation Circ. Res., March 3, 2000; 86(4): 448 - 455. [Abstract] [Full Text] [PDF]

				A. O. Verkerk, M. W. Veldkamp, F. Abbate, G. Antoons, L. N. Bouman, J. H. Ravesloot, and A. C. G. van Ginneken Two types of action potential configuration in single cardiac Purkinje cells of sheep Am J Physiol Heart Circ Physiol, October 1, 1999; 277(4): H1299 - H1310. [Abstract] [Full Text] [PDF]

				D. J. Huelsing, K. W. Spitzer, J. M. Cordeiro, and A. E. Pollard Conduction between isolated rabbit Purkinje and ventricular myocytes coupled by a variable resistance Am J Physiol Heart Circ Physiol, April 1, 1998; 274(4): H1163 - H1173. [Abstract] [Full Text] [PDF]

				P. Taggart, P. M.I. Sutton, M. R. Boyett, M. Lab, and H. Swanton Human Ventricular Action Potential Duration During Short and Long Cycles: Rapid Modulation by Ischemia Circulation, November 15, 1996; 94(10): 2526 - 2534. [Abstract] [Full Text]

				C. Jeck, J. Pinto, and P. Boyden Transient Outward Currents in Subendocardial Purkinje Myocytes Surviving in the Infarcted Heart Circulation, August 1, 1995; 92(3): 465 - 473. [Abstract] [Full Text]

				J. Zeng, K. R. Laurita, D. S. Rosenbaum, and Y. Rudy Two Components of the Delayed Rectifier K+ Current in Ventricular Myocytes of the Guinea Pig Type : Theoretical Formulation and Their Role in Repolarization Circ. Res., July 1, 1995; 77(1): 140 - 152. [Abstract] [Full Text]