Summary
Under normal experimental conditions, the force of rested-state contractions (i.e., contractions after a rest period of 15 min or longer) of mammalian ventricular myocardium is insignificant. In Mg2+-free solution, in low sodium solution or in the presence of a cardioactive steroid, a strong “early” restedstate contraction develops without delay after stimulation, indicating the accumulation during rest of intracellularly stored activator calcium. By contrast, catecholamines cause a “late” rested-state contraction with a characteristic latent period of about 100 ms between stimulation and onset of contraction.
Inhibition of the slow inward current by nifedipine has no influence on the contraction velocity of the “early” rested-state contraction, indicating that Ca2+ of the slow inward current is not involved in the calcium release mechanism of prefilled stores during excitation-contraction coupling. Nifedipine suppresses the “late” rested-state contraction in the presence of noradrenaline. In view of the constancy of the latent period, it is proposed that the activator calcium for the “late” rested-state contraction enters the cell with the slow inward current, is sequestered at first by uptake sites of the sarcoplasmic reticulum and subsequently released from its release sites as long as the cell is depolarized.
The model of the different origin of activator calcium is discussed, in its implication for high-frequency contractions.
References
anderson TW, Hirsch C, Kavaler F (1977) Mechanism of activation of contraction in frog ventricular muscle. Circul Res 41:472–480
Antoni H, Jacob R, Kaufmann R (1969) Mechanische Reaktionen des Frosch- und Säugetiermyokards bei Veränderung der Aktionspotential-Dauer durch konstante Gleichstromimpulse. Pflügers Arch 306:33–57
Allen DG, Jewell BR, Wood EH (1976) Studies of the contractility of mammalian myocardium at low rates of stimulation. J Physiol (Lond) 254:1–17
Bassingthwaighte JB, Fry CH, McGuigan JAS (1976) Relationship between internal calcium and outward current in mammalian ventricular muscle; a mechanism for the control of the action potential duration? J Physiol (Lond.) 262:15–37
Bcręsewicz A, Reuter H (1977) The effects of adrenaline and theophylline on action potential and contraction of mammalian ventricular muscle under “rested-state” and “steady-state” stimulation. Naunyn-Schmiedeberg's Arch Pharmacol 301:99–107
Blinks JR, Koch-Weser J (1961) Analysis of the effects of changes in rate and rhythm upon myocardial contractility. J Pharmacol Exp Ther 134:373–389
Carafoli E (1981) Ca2+ pumping systems in dog heart sarcolemma. J Mol Cell Cardiol 13(Suppl 1):14 (Abstract)
Endo M (1977) Calcium release from the sarcoplasmic reticulum. Pharmacol Rev 57:71–108
Fabiato A (1983) Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum. Am J Physiol 245 (Cell Physiol 14):C1-C14
Hasselbach W, Oetliker H (1983) Energetics and electrogenicity of the sarcoplasmic reticulum calcium pump. Ann Rev Physiol 45:325–339
Kohlhardt M, Fleckenstein A (1977) Inhibition of the slow inward current by nifedipine in mammalian ventricular myocardium. Naunyn-Schmiedeberg's Arch Pharmacol 298:267–272
Lewartowsky B, Prokopczuk A, Pytkowski B (1978) Effect of inhibitors of slow calcium current on rested state contraction of papillary muscles and post rest contractions of atrial muscle of the cat and rabbit hearts. Pflügers Arch 377:167–175
McDonald TF, Pelzer D, Trautwein W (1981) Does the calcium current modulate the contraction of the accompanying beat? A study of E-C coupling in mammalian ventricular muscle using cobalt ions. Circ Res 49:576–583
Morad M, Goldman YE, Trentham DR (1983) Rapid photochemical inactivation of Ca2+-antagonists shows that Ca2+ entry directly activates contraction in frog heart. Nature 304:635–638
Mulieri LA, Alpert NR (1982) Activation heat and latency relaxation in relation to calcium movement in skeletal and cardiac muscle. Can J Physiol Pharmacol 60:529–541
Mullins LJ (1981) Ion transport in heart. Raven Press, New York
Niedergerke R, Ogden DC, Page S (1976) Contractile activation and calcium movements in heart cells. In: Symposia of the Society for Experimental Biology, No 30, Calcium in biological systems. University Press, Cambridge, pp 381–395
Reiter M, Seibel K, Karema E (1978) The inotropic action of noradrenaline on rested-state contractions of guinea-pig cardiac ventricular muscle. Life Sci, 22:1149–1158
Reiter M, Vierling W, Seibel K (1984) Excitation-contraction coupling in rested-state contractions of guinea-pig ventricular myocardium. Naunyn-Schmiedeberg's Arch Pharmacol 325:159–169
Reuter H, Stevens CF, Tsien RW, Yellen G (1982) Properties of single calcium channels in cardiac cell culture. Nature 297:501–504
Robison GA, Butcher RW, Øye I, Morgan HE, Sutherland EW (1965) The effect of epinephrine on adenosine 3′5′-phsophate levels in the isolated perfused rat heart. Mol Pharmacol 1:168–177
Seibel K, Karema E, Takeya K, Reiter M (1976) Two components of heart muscle contraction under the influence of noradrenaline. Naunyn-Schmiedeberg's Arch Pharmacol 294:R 19 (Abstract)
Seibel K, Karema E, Takeya K, Reiter M (1978) Effect of noradrenaline on an early and a late component of the myocardial contraction. Naunyn-Schmiedeberg's Arch Pharmacol 305:65–74
Simurda J, Simurdova M, Braveny P, Sumbera J (1976) Slow inward current and action potentials of papillary muscles under non-steady state conditions. Pflügers Arch 362:209–218
Solaro RJ, Moir AJG, Perry SV (1976) Phosphorylation of troponin I and the inotropic effect of adrenaline in the perfused rabbit heart. Nature 262:615–617
Sommer JR, Johnson EA (1979) Ultrastructure of cardiac muscle. In: Handbook of physiology—the cardiovascular system, I. Bethesda, Maryland, USA, pp 113–186
Tada M, Katz AM (1982) Phosphorylation of the sarcoplasmic reticulum and sarcolemma. Ann Rev Physiol 44:401–423
Trautwein W, McDonald TF, Tripathi O (1975) Calcium conductance and tension in mammalian ventricular muscle. Pflügers Arch 354:55–74
Vierling W, Reiter M (1975) Frequency-force relationship in guinea-pig ventricular myocardium as influenced by magnesium. Naunyn-Schmiedeberg's Arch Pharmacol 289:111–125
Weidmann S (1959) Effect of increasing the calcium concentration during a single heart-beat. Experientia 15:128
Wendt-Gallitelli MF, Jacob R, Wolburg H (1982) Intracellular membranes as boundaries for ionic distribution. In situ elemental distribution in guinea pig heart muscle in different defined electromechanical coupling states. Z Naturforsch 37c:712–720
Winegrad S (1968) Intracellular calcium movements of frog skeletal muscle during recovery from tetanus. J Gen Physiol 51:65–83
Wohlfart B, Noble MIM (1982) The cardiac excitation-contraction cycle. Pharmacol Ther 16:1–43
Wood EH, Heppner RL, Weidmann S (1969) Inotropic effects of electric currents. Circul Res 24:409–445
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Reiter, M., Vierling, W. & Seibel, K. Where is the origin of the activator calcium in cardiac ventricular contraction?. Basic Res Cardiol 79, 1–8 (1984). https://doi.org/10.1007/BF01935801
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DOI: https://doi.org/10.1007/BF01935801