Abstract
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 (+E max) 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 (+V max) increases from about 20 v/sec at days 2–3 to 150 v/sec at days 18–21; + V max 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 MΩ at day 2 vs. 4.5 MΩ at days 8–21), suggesting that the membrane resistivity (Rm) is higher. The ratio of permeabilities, P Na/P K, is high (about 0.2) in young hearts, due to a low P K, and decreases during ontogeny (to about 0.05). The low K+ conductance (g K) 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 g K of young or old ventricular cells. The increase in (Na+, K+)-adenosine triphosphatase (ATPase) activity during development tends to compensate for the increase in g K. +E max and + V max 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.
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- Boethius J., Knutsson E. Resting membrane potential in chick muscle cells during ontogeny. J Exp Zool. 1970 Jul;174(3):281–286. doi: 10.1002/jez.1401740304. [DOI] [PubMed] [Google Scholar]
- Boëthius J. Resting membrane potential in neck and leg muscles of young rats. Acta Physiol Scand. 1969 Jan-Feb;75(1):253–254. doi: 10.1111/j.1748-1716.1969.tb04377.x. [DOI] [PubMed] [Google Scholar]
- Coraboeuf E., Obrecht-Coutris G., Le Douarin G. Acetylcholine and the embryonic heart. Am J Cardiol. 1970 Mar;25(3):285–291. doi: 10.1016/s0002-9149(70)80005-4. [DOI] [PubMed] [Google Scholar]
- DeHaan R. L. The potassium-sensitivity of isolated embryonic heart cells increases with development. Dev Biol. 1970 Oct;23(2):226–240. doi: 10.1016/0012-1606(70)90096-5. [DOI] [PubMed] [Google Scholar]
- DeHann R. L. Regulation of spontaneous activity and growth of embryonic chick heart cells in tissue culture. Dev Biol. 1967 Sep;16(3):216–249. doi: 10.1016/0012-1606(67)90025-5. [DOI] [PubMed] [Google Scholar]
- Dominguez G., Fozzard H. A. Influence of extracellular K+ concentration on cable properties and excitability of sheep cardiac Purkinje fibers. Circ Res. 1970 May;26(5):565–574. doi: 10.1161/01.res.26.5.565. [DOI] [PubMed] [Google Scholar]
- ENEMAR A., FALCK B. OBSERVATIONS ON THE APPEARANCE OF NOREPINEPHRINE IN THE SYMPATHETIC NERVOUS SYSTEM OF THE CHICK EMBRYO. Dev Biol. 1965 Apr;11:268–283. doi: 10.1016/0012-1606(65)90060-6. [DOI] [PubMed] [Google Scholar]
- FINGL E., WOODBURY L. A., HECHT H. H. Effects of innervation and drugs upon direct membrane potentials of embryonic chick myocardium. J Pharmacol Exp Ther. 1952 Jan;104(1):103–114. [PubMed] [Google Scholar]
- Garnier D., Rougier O., Gargouïl Y. M., Coraboeuf E. Analyse électrophysiologique du plateau des réponses myocardiques, mise en évidence d'un courant lent entrant en absence d'ions bivalents. Pflugers Arch. 1969;313(4):321–342. doi: 10.1007/BF00593957. [DOI] [PubMed] [Google Scholar]
- HARSCH M., GREEN J. W. ELECTROLYTE ANALYSES OF CHICK EMBRYONIC FLUIDS AND HEART TISSUES. J Cell Physiol. 1963 Dec;62:319–326. doi: 10.1002/jcp.1030620312. [DOI] [PubMed] [Google Scholar]
- HIBBS R. G. Electron microscopy of developing cardiac muscle in chick embryos. Am J Anat. 1956 Jul;99(1):17–51. doi: 10.1002/aja.1000990103. [DOI] [PubMed] [Google Scholar]
- Hermsmeyer K., Sperelakis N. Decrease in K+ conductance and depolarization of frog cardiac muscle produced by Ba++. Am J Physiol. 1970 Oct;219(4):1108–1114. doi: 10.1152/ajplegacy.1970.219.4.1108. [DOI] [PubMed] [Google Scholar]
- KLEIN R. L. Ontogenesis of K and Na fluxes in embryonic chick heart. Am J Physiol. 1960 Oct;199:613–618. doi: 10.1152/ajplegacy.1960.199.4.613. [DOI] [PubMed] [Google Scholar]
- KLEIN R. L. THE INDUCTION OF A TRANSFER ADENOSINE TRIPHOSPHATE PHOSPHOHYDROLASE IN EMBRYONIC CHICK HEART. Biochim Biophys Acta. 1963 Jul 9;73:488–498. doi: 10.1016/0006-3002(63)90450-5. [DOI] [PubMed] [Google Scholar]
- LEHMKUHL D., SPERELAKIS N. TRANSMEMBRANE POTENTIALS OF TRYPSIN-DISPERSED CHICK HEART CELLS CULTURED IN VITRO. Am J Physiol. 1963 Dec;205:1213–1220. doi: 10.1152/ajplegacy.1963.205.6.1213. [DOI] [PubMed] [Google Scholar]
- Pappano A. J. Sodium-dependent depolarization of noninnervated embryonic chick heart by acetylcholine. J Pharmacol Exp Ther. 1972 Feb;180(2):340–350. [PubMed] [Google Scholar]
- Pappano A. J., Sperelakis N. Low K+ conductance and low resting potentials of isolated single cultured heart cells. Am J Physiol. 1969 Oct;217(4):1076–1082. doi: 10.1152/ajplegacy.1969.217.4.1076. [DOI] [PubMed] [Google Scholar]
- Redfern P., Thesleff S. Action potential generation in denervated rat skeletal muscle. II. The action of tetrodotoxin. Acta Physiol Scand. 1971 May;82(1):70–78. doi: 10.1111/j.1748-1716.1971.tb04943.x. [DOI] [PubMed] [Google Scholar]
- Renaud D., Le Douarin G. Mise en évidence, par l'emploi d'inhibiteurs, d'une évolution des perméabilités membranaires cardiaques aux jeunes stades du dévelopment chez l'embryon de poulet. C R Acad Sci Hebd Seances Acad Sci D. 1972 Jan 17;274(3):418–421. [PubMed] [Google Scholar]
- Rougier O., Vassort G., Garnier D., Gargouil Y. M., Coraboeuf E. Existence and role of a slow inward current during the frog atrial action potential. Pflugers Arch. 1969;308(2):91–110. doi: 10.1007/BF00587018. [DOI] [PubMed] [Google Scholar]
- Shigenobu K., Sperelakis N. Development of sensitivity to tetrodotoxin of chick embryonic hearts with age. J Mol Cell Cardiol. 1971 Dec;3(3):271–286. doi: 10.1016/0022-2828(71)90046-0. [DOI] [PubMed] [Google Scholar]
- Shimizu Y., Tasaki K. Electrical excitability of developing cardiac muscle in chick embryos. Tohoku J Exp Med. 1966 Jan 25;88(1):49–56. doi: 10.1620/tjem.88.49. [DOI] [PubMed] [Google Scholar]
- Sperelakis N. (Na + , K + )-ATPase activity of embryonic chick heart and skeletal muscles as a function of age. Biochim Biophys Acta. 1972 Apr 14;266(1):230–237. doi: 10.1016/0005-2736(72)90137-x. [DOI] [PubMed] [Google Scholar]
- Sperelakis N. Lack of electrical coupling between contiguous myocardial cells in vertebrate hearts. Experientia Suppl. 1969;15:135–165. doi: 10.1007/978-3-0348-6800-6_10. [DOI] [PubMed] [Google Scholar]
- Sperelakis N., Lee E. C. Characterization of (Na + ,K + )-ATPase isolated from embryonic chick hearts and cultured chick heart cells. Biochim Biophys Acta. 1971 Jun 1;233(3):562–579. doi: 10.1016/0005-2736(71)90155-6. [DOI] [PubMed] [Google Scholar]
- Sperelakis N., Lehmkuhl D. Ba 2+ AND Sr 2+ reversal of the inhibition produced by ouabain and local anesthetics on membrane potentials of cultured heart cells. Exp Cell Res. 1968 Feb;49(2):396–410. doi: 10.1016/0014-4827(68)90189-4. [DOI] [PubMed] [Google Scholar]
- Sperelakis N., Lehmkuhl D. Insensitivity of cultured chick heart cells to autonomic agents and tetrodotoxin. Am J Physiol. 1965 Oct;209(4):693–698. doi: 10.1152/ajplegacy.1965.209.4.693. [DOI] [PubMed] [Google Scholar]
- Sperelakis N., Lehmkuhl D. Ionic interconversion of pacemaker and nonpacemaker cultured chick heart cells. J Gen Physiol. 1966 May;49(5):867–895. doi: 10.1085/jgp.49.5.867. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sperelakis N., Mayer G., Macdonald R. Velocity of propagation in vertebrate cardiac muscles as functions of tonicity and [K+]. Am J Physiol. 1970 Oct;219(4):952–963. doi: 10.1152/ajplegacy.1970.219.4.952. [DOI] [PubMed] [Google Scholar]
- Sperelakis N., Schneider M. F., Harris E. J. Decreased K+ conductance produced by Ba++ in frog sartorius fibers. J Gen Physiol. 1967 Jul;50(6):1565–1583. doi: 10.1085/jgp.50.6.1565. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TRAUTWEIN W. Generation and conduction of impulses in the heart as affected by drugs. Pharmacol Rev. 1963 Jun;15:277–332. [PubMed] [Google Scholar]
- Tuganowski W., Cekański A. Electrical activity of a single fibre of the human embryonic heart. Pflugers Arch. 1971;323(1):21–26. doi: 10.1007/BF00586562. [DOI] [PubMed] [Google Scholar]
- Vereecke J., Carmeliet E. Sr action potentials in cardiac Purkyne fibres. II. Dependence of the Sr conductance on the external Sr concentration and Sr-Ca antagonism. Pflugers Arch. 1971;322(1):73–82. doi: 10.1007/BF00586666. [DOI] [PubMed] [Google Scholar]
- Yeh B. K., Hoffman B. F. The ionic basis of electrical activity in embryonic cardiac muscle. J Gen Physiol. 1968 Oct;52(4):666–681. doi: 10.1085/jgp.52.4.666. [DOI] [PMC free article] [PubMed] [Google Scholar]