Abstract
The relative importance of the sarcoplasmic reticulum (SR) as a source of Ca2+ in the excitation-contraction coupling of mammalian myocytes was tested. Shortening and intracellular Ca2+ transients of electrically paced, isolated,adult rat myocytes were found to be absolutely dependent on the presence of a functional SR and were completely abolished by the SR Ca2+-ATPase inhibitors cyclopiazonic acid and thapsigargin or by the Ca2+-release channel opener ryanodine.Neonatal rat cardiomyocytes, on the other hand, elicited consistent intracellular Ca2+-transients even after complete functional inhibition of the SR. The transients, however, were markedly prolonged. Also isolatedadult guinea pig myocytes maintained the ability to shorten after a complete inhibition of the SR Ca2+-ATPase by either thapsigargin or cyclopiazonic acid. The twitches and the intracellular Ca2+-transients, however, were considerably longer after inhibition of the SR Ca2+-ATPase. Different results were obtained after preincubation of the cells with 10 μM ryanodine to induce emptying of the SR Ca2+ pool. In this case, Ca2+ spikes and twitches were also markedly reduced in size, in addition to being prolonged. When a SR Ca2+-pump inhibitor was added to ryanodine-treated cells, the size of the Ca2+-transients and the capacity of the cells to shorten increased. Ryanodine leaves the activity of the Ca2+-pump of the SR intact and thus leads to an underestimation of the amount of excitatory Ca2+-flowing into the cell.
The results show that, while the significance of the SR in regulating the Ca2+-transients and shortening of cardiomyocytes varies depending on the species and the stage of development, SR function is of paramount importance for the occurrence of rapid twitches.
Similar content being viewed by others
Abbreviations
- EGTA:
-
ethylene glycol-bis-(beta amino ethyl ether)N,N,N′,N′ tetraacetic acid
- MOPS:
-
morpholinopropane sulfonic acid
- SR:
-
sarcoplasmic reticulum
- BSA:
-
bovine serum albumin
- HEPES:
-
N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid
References
Mahony L, Jones LR: Developmental changes in cardiac SR in sheep. J Biol Chem 261: 15257–15265, 1986
Nakanishi T, Jarmakani JM: Developmental changes in myocardial mechanical function and subcellular organelles. Am J Physiol 246: H615-H625, 1984
Vetter R, Kemsies C, Schulze W: Sarcolemmal Na−Ca exchanger and sarcoplasmic reticulum Ca uptake in several cardiac preparations. Biomed Biochim Acta 46: 375–381, 1987
Jarmakani JM, Nakanishi T, George BL, Bers D: Effect of extracellular Ca2+ on myocardial mechanical function in the neonatal rabbit. Dev Pharmacol Ther 5: 1–13, 1982
Nishioka K, Nakanishi T, George BL, Jarmakani JM: The effect of Ca2+ on the inotropy of catecholamine and paired electrical stimulation in the newborn and adult myocardium. J Mol Cell Cardiol 13: 511–520, 1981
Artman M: Sarcolemmal Na−Ca exchange activity and exchanger immunoreactivity in developing rabbit hearts. Am J Physiol 263: H1506-H1513, 1992
Seidler NW, Jonal I, Vegh M, Martonosi A: Cyclopiazonic acid is a specific inhibitor of the Ca2+-ATPase os SR. J Biol Chem 264: 17816–17823, 1989
Uyama Y, Imaizumi Y, Watanabe M: Effects of cyclopiazonic acid, a novel Ca2+-ATPase inhibitor, on contractile responses in skinned ileal smooth muscle. Br J Pharmacol 106: 208–214, 1992
Thastrup O, Dawson AP, Scharff O, Foder B, Cullen PJ, Drobak BK, Bierrum PJ, Christensen SB, Hanley MR: Thapsigargin, a novel molecular probe for studying intracellular Ca2+ release and storage. Agents and Actions 27: 17–23, 1989
Inesi G, Sagara Y: Thapsigargin, a high affinity and global inhibitor of intracellular Ca2+ transport ATPases. Arch Biochem Biophys 298: 313–317, 1992
Wrzosek A, Schneider H, Grueninger S, Chiesi M: Effect of thapsigargin on cardiac muscle cells. Cell Calcium 13: 281–292, 1992
Mason MJ, Garcia-Rodriguez C, Grinstein S: Coupling between intracellular Ca2+-stores and the Ca2+-permeability of the plasma membrane. J Biol Chem 266: 20856–20862, 1991
Chamberlain BK, Levitsky DO, Fleischer S: Isolation and characterization of canine cardiac sarcoplasmic reticulum with improved Ca2+ transport properties. J Biol Chem 258: 6602–6609, 1983
Mitra R, Morad M: A uniform enzymatic method for dissociation of myocytes from hearts and stomachs of vertebrates. Am J Physiol 249: H1056-H1060, 1985
Achenbach C, Wiemer J, Preisler R: Isolation of adult ventricular myocytes for electrophysiological experiments. Basic Res Cardiol 80: Sup 1, 162, 1985
Henderson SA, Spencer M, Sen A, Kumar Ch, Siddiqui MAQ, Chien KR: Structure, organization and expression of the rat cardiac myosin light chain-2 gene. J Biol Chem 264: 18142–18148, 1989
Rohrer DK, Hartong R, Dillmann WH: Influence of Thyroid hormone and retinoic acid on slow SR Ca2+-ATPase and myosin chain gene expression in cardiac myocytes. J Biol Chem 266: 8638–8646, 1991
Chiesi M, Inesi G: The use of quench reagents for resolution of single transport cycles in SR. J Biol Chem 254: 10370–10377, 1979
Jones LR, Besch HR, Sutko JL, Willerson JT: Ryanodine induced stimulation of net calcium uptake by cardiac SR vesicles. J Biol Chem 209: 48–55, 1979
Fleischer S, Ogunbunmi EM, Dixon MC, Fleer EAM: Localization of calcium release channels with ryanodine in junctional terminal cisternae of SR in fast skeletal muscle. Proc Natl Acad Sci USA 82: 7256–7259, 1985
Lewartowski B, Wolska BM: The effect of thapsigargin on SR Cacontent and contractions in single myocytes of guinea-pig heart. J Molec Cell Cardiol 25: 23–29, 1993
Kirby MS, Sagara Y, Gaa S, Inesi G, Lederer WJ, Rogers TB: Thapsigargin inhibits contraction and Ca transient in cardiac cells by specific inhibition of the SR Ca pump. J Biol Chem 267: 12545–12551, 1992
Swynghedauw B: Changes in membrane proteins in chronic mechanical overload of the heart. Am J Cardiol 65: 30G-33G, 1990
Reinecke H, Studer R, Philipson KD, Bilger J, Eschenhagen T, Boehm M, Just H, Holtz J, Drexler H: Myocardial gene expression of Na−Ca-exchanger and SR Ca-ATPase in human heart failure. Circ 86 (Suppl I): I-860, 1992
Marban E, Wier WG: Ryanodine as a tool to determine the contributions of calcium entry and calcium release to the calcium transient and contraction of cardiac Purkinje fibers. Circ Res 56: 133–138, 1985
Beuckelmann DJ, Wier WG: Mechanism of release of calcium from SR of guinea-pig cardiac cells. J Physiol 405: 233–255, 1988
Buck E, Zimanyi I, Abramson JJ, Pessah IN: Ryanodine stabilizes multiple conformational states of the skeletal muscle calcium release channel. J Biol Chem 267: 23560–23567, 1992
Lewartowski B, Hansford RG, Langer GA, Lakatta EG: Contraction and SR Calcium content in single myocytes of guinea-pig heart: effect of ryanodine. Am J Physiol 259: H1222-H1229 1990
Schuettler K, Wang SY, Pfeifer T, Meyer R: Late contraction in guinea pig ventricular myocytes activated by the Na−Ca exchange during the action potential. Ann N.Y. Acad Sci 639: 475–477, 1991
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Chiesi, M., Wrzosek, A. & Grueninger, S. The role of the sarcoplasmic reticulum in various types of cardiomyocytes. Mol Cell Biochem 130, 159–171 (1994). https://doi.org/10.1007/BF01457397
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01457397