The Journal of General Physiology
World Precision Insruments
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text (PDF, 1355K)
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JGP
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Sperelakis, N.
Right arrow Articles by Shigenobu, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Sperelakis, N.
Right arrow Articles by Shigenobu, K.
Right arrowPubmed/NCBI databases
*Compound via MeSH
*Substance via MeSH
Hazardous Substances DB
*POTASSIUM
*SODIUM
*TETRODOTOXIN
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
The Journal of General Physiology, Vol 60, 430-453, Copyright © 1972 by The Rockefeller University Press

ARTICLE

Changes in Membrane Properties of Chick Embryonic Hearts during Development

Nick Sperelakis 1 and K. Shigenobu 1

1 From the Department of Physiology, University of Virginia School of Medicine, Charlottesville, Virginia 22903

The electrophysiological properties of embryonic chick hearts (ventricles) change during development; the largest changes occur between days 2 and 8. Resting potential (Em) and peak overshoot potential (+Emax) increase, respectively, from -35 mv and +11 mv at day 2 to -70 mv and +28 mv at days 12–21. Action potential duration does not change significantly. Maximum rate of rise of the action potential (+Vmax) increases from about 20 v/sec at days 2–3 to 150 v/sec at days 18–21; + Vmax of young cells is not greatly increased by applied hyperpolarizing current pulses. In resting Em vs. log [K+]o curves, the slope at high K+ is lower in young hearts (e.g. 30 mv/decade) than the 50–60 mv/decade obtained in old hearts, but the extrapolated [K+]i values (125–140 mM) are almost as high. Input resistance is much higher in young hearts (13 Mohm at day 2 vs. 4.5 Mohm at days 8–21), suggesting that the membrane resistivity (Rm) is higher. The ratio of permeabilities, PNa/PK, is high (about 0.2) in young hearts, due to a low PK, and decreases during ontogeny (to about 0.05). The low K+ conductance (gK) in young hearts accounts for the greater incidence of hyperpolarizing afterpotentials and pacemaker potentials, the lower sensitivity (with respect to loss of excitability) to elevation of [K+]o, and the higher chronaxie. Acetylcholine does not increase gK of young or old ventricular cells. The increase in (Na+, K+)-adenosine triphosphatase (ATPase) activity during development tends to compensate for the increase in gK. +Emax and + Vmax are dependent on [Na+]o in both young and old hearts. However, the Na+ channels in young hearts (2–4 days) are slow, tetrodotoxin (TTX)-insensitive, and activated-inactivated at lower Em. In contrast, the Na+ channels of cells in older hearts (> 8 days) are fast and TTX-sensitive, but they revert back to slow channels when placed in culture.

Submitted on January 5, 1972


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
 J. Physiol.Home page
H. Zhang, N. Shepherd, and T. L. Creazzo
Temperature-sensitive TREK currents contribute to setting the resting membrane potential in embryonic atrial myocytes
J. Physiol., August 1, 2008; 586(15): 3645 - 3656.
[Abstract] [Full Text] [PDF]

Home page
 Physiol. GenomicsHome page
M. D. Harrell, S. Harbi, J. F. Hoffman, J. Zavadil, and W. A. Coetzee
Large-scale analysis of ion channel gene expression in the mouse heart during perinatal development
Physiol Genomics, February 12, 2007; 28(3): 273 - 283.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
T. Krogh-Madsen, P. Schaffer, A. D. Skriver, L. K. Taylor, B. Pelzmann, B. Koidl, and M. R. Guevara
An ionic model for rhythmic activity in small clusters of embryonic chick ventricular cells
Am J Physiol Heart Circ Physiol, July 1, 2005; 289(1): H398 - H413.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
J. Satin, I. Kehat, O. Caspi, I. Huber, G. Arbel, I. Itzhaki, J. Magyar, E. A. Schroder, I. Perlman, and L. Gepstein
Mechanism of spontaneous excitability in human embryonic stem cell derived cardiomyocytes
J. Physiol., September 1, 2004; 559(2): 479 - 496.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
J.-Q. He, Y. Ma, Y. Lee, J. A. Thomson, and T. J. Kamp
Human Embryonic Stem Cells Develop Into Multiple Types of Cardiac Myocytes: Action Potential Characterization
Circ. Res., July 11, 2003; 93(1): 32 - 39.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
T. A. McBride, B. W. Stockert, F. A. Gorin, and R. C. Carlsen
Stretch-activated ion channels contribute to membrane depolarization after eccentric contractions
J Appl Physiol, January 1, 2000; 88(1): 91 - 101.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
E. T. Chuck, D. M. Freeman, M. Watanabe, and D. S. Rosenbaum
Changing Activation Sequence in the Embryonic Chick Heart : Implications for the Development of the His-Purkinje System
Circ. Res., October 19, 1997; 81(4): 470 - 476.
[Abstract] [Full Text]

Home page
 ScienceHome page
M. McLean, J Renaud, N Sperelakis, and M. Niu
Messenger RNA induction of fast sodium ion channels in cultured cardiac myoblasts
Science, January 23, 1976; 191(4224): 297 - 299.
[Abstract] [PDF]


  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents