| dc.creator | Bassani R. | |
| dc.date | 1997 | |
| dc.date | 2015-06-30T14:48:41Z | |
| dc.date | 2015-11-26T14:17:55Z | |
| dc.date | 2015-06-30T14:48:41Z | |
| dc.date | 2015-11-26T14:17:55Z | |
| dc.date.accessioned | 2018-03-28T21:19:05Z | |
| dc.date.available | 2018-03-28T21:19:05Z | |
| dc.identifier | | |
| dc.identifier | American Journal Of Physiology - Heart And Circulatory Physiology. , v. 42, n. 2, p. H886 - H892, 1997. | |
| dc.identifier | 3636135 | |
| dc.identifier | | |
| dc.identifier | http://www.scopus.com/inward/record.url?eid=2-s2.0-33751286639&partnerID=40&md5=25fc0d7ca1a084de8f1afd43feec1d44 | |
| dc.identifier | http://www.repositorio.unicamp.br/handle/REPOSIP/100116 | |
| dc.identifier | http://repositorio.unicamp.br/jspui/handle/REPOSIP/100116 | |
| dc.identifier | 2-s2.0-33751286639 | |
| dc.identifier.uri | http://repositorioslatinoamericanos.uchile.cl/handle/2250/1243475 | |
| dc.description | Evidence has shown that the sarcoplasmic reticulum (SR) of cardiac cells releases Ca not only during excitation-contraction coupling but also during diastole, albeit at a much lower rate. This diastolic SR Ca release (leak) has also been implicated in the generation of spontaneous depolarization in latent atrial pacemaker cells of the cat right atrium. In the present work, we sought to measure Ca transients in pacemaker and nonpacemaker cells of the cat using the fluorescent Ca indicator indo 1. Atrial latent pacemaker cells develop a slow Ca transient when rested in the presence of both Na- and Ca-free solution and thapsigargin [used to inhibit Na/Ca exchange and SR Ca adenosinetriphosphatase (Ca-ATPase), respectively]. This increase in cytosolic Ca concentration ([Ca]j) is probably caused by the rate of SR Ca leak exceeding the capacity of the remaining Ca transport systems (e.g., sarcolemmal Ca-ATPase and mitochondria! Ca uptake). However, neither cat sinoatrial (SA) node cells nor myocytes from cat atrium or ventricle exhibited a similar increase in [Ca]j during the same protocol. This indicates that SR Ca leak in these cells occurred at a rate low enough to be within the capacity of the slow Ca transporters, as observed previously in rabbit ventricular myocytes. When atrial and ventricular myocytes were stimulated at higher frequencies, sufficient to markedly increase diastolic and systolic [Ca]; and approach Ca overload (and spontaneous activity), they responded to inhibition of SR Ca-ATPase and Na/Ca exchange with a slow Ca transient similar to that normally observed in atrial latent pacemaker cells. Furthermore, the SR Ca depletion by thapsigargin did not affect spontaneous activity of SA node cells, but it prevented or slowed pacemaker activity in the atrial latent pacemaker cells. These findings suggest that enhanced diastolic SR Ca efflux contributes significantly to the generation of spontaneous activity in atrial subsidiary pacemakers under normal conditions and in Ca-overloaded myocytes but not in S A node cells. sinoatrial node cells; sarcoplasmic reticulum calcium release; thapsigargin; calcium transients; automaticity Copyright © 1997 the American Physiological Society. | |
| dc.description | 42 | |
| dc.description | 2 | |
| dc.description | H886 | |
| dc.description | H892 | |
| dc.description | Bassani, R.A., Bassani, J.W.M., Bers, D.M., Mitochondrial and sarcolemmal Ca 2+ transport reduce Ca2 during caffeine contractures in rabbit cardiac myocytes (1992) J. Physiol. (Lond.), 453, pp. 591-608 | |
| dc.description | Bassani, J.W.M., Bassani, R.A., Bers, D.M., Relaxation in rabbit and rat cardiac cells: Species-dependent differences in cellular mechanisms (1994) J. Physiol. (Lond.), 476, pp. 279-293 | |
| dc.description | Bassani, R.A., Bers, D.M., Na-Ca exchange is required for rest-decay but not for rest-potentiation of twitches in rabbit and rat ventricular myocytes (1994) J. Mol. Cell. Cardiol., 26, pp. 1335-1347 | |
| dc.description | Bassani, R.A., Bers, D.M., Rate of diastolic Ca release from the sarcoplasmic reticulum of intact rabbit and rat ventricular myocytes (1995) Biophys. J., 68, pp. 2015-2022 | |
| dc.description | Bassani, J.W.M., Yuan, W., Bers, D.M., Fractional SR Ca release is regulated by trigger Ca and SR Ca content in cardiac myocytes (1995) Am. J. Physiol., 268, pp. C1313-C1329. , (Cell Physiol. 37) | |
| dc.description | Bers, D.M., Dordrecht, the Netherlands: Kluwer Academic Excitation-Contraction Coupling and Cardiac Contractile Force., , 1991, p. 258 | |
| dc.description | Bers, D.M., Bassani, R.A., Bassani, J.W.M., Baudet, S., Hryshko, L.V., Paradoxical twitch potentiation after rest in cardiac muscle: Increased fractional release of SR calcium (1993) J. Mol. Cell. Cardiol., 25, pp. 1047-1057 | |
| dc.description | Bridge, J.H.B., Relationships between the sarcoplasmic reticulum and transsarcolemmal Ca transport revealed by rapid cooling contractures (1986) J. Gen. Physiol., 88, pp. 437-473 | |
| dc.description | Brown, H.F., Kimura, J., Noble, D., Noble, S.J., Taupignon, A., The slow inward current, t-si, in the rabbit sino' atrial node investigated by voltage-clamp and computer simulation (1984) Proc. R. Soc. Lond. B Biol. Sei., 222, pp. 305-328 | |
| dc.description | Cheng, H., Lederer, W.J., Cannell, M.B., Calcium sparks: Elementary events underlying excitation-contraction coupling in heart muscle (1993) Science, 262, pp. 740-744 | |
| dc.description | Di Francesco, D., Noble, D., A model of cardiac electric activity incorporating ionic pumps and concentration changes (1985) Philos. Trans. R. Soc. Lond. B Biol. Sei., 307, pp. 353-398 | |
| dc.description | Fabiato, A., Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum (1983) Am. J. Physiol., 245, pp. C1-C14. , (Cell Physiol. 14) | |
| dc.description | Hiiser, J., Lipsius, S.L., Blatter, L.A., Calcium gradients during excitation-contraction coupling in cat atrial myocytes (1996) J. Physiol. (Lond.), 494, pp. 641-651 | |
| dc.description | Jones, S.B., Euler, D.E., Randall, W.C., Brynjolfsson, G., Hardie, E.L., Atrial ectopic foci in the canine heart: Hierarchy of pacemaker automaticity (1980) Am. J. Physiol., 238, pp. H788-H793. , (Heart Circ. Physiol. 7) | |
| dc.description | Langer, Peskoff, A., Calcium concentration and movements in the diadic cleft space of the cardiac ventricular cell (1996) Biophys. J., 70, pp. 1169-1182 | |
| dc.description | Lipsius, S.L., Rubenstein, D.S., Zhou, Z., Cellular mechanisms of right atrial latent pacemakers (1993) New Trends Arrhythmias, 19, pp. 11-23 | |
| dc.description | Negretti, N., O'Neill, S.R., Eisner, D.A., The relative contributions of different intracellular and sarcolemmal systems to relaxation in rat ventricular myocytes (1993) Cardiovasc. Res., 27, pp. 1826-1830 | |
| dc.description | Orchard, C.H., Cingolani, H.E., Acidosis and arrhythmias in cardiac muscle (1994) Cardiovasc. Res., 28, pp. 1312-1319 | |
| dc.description | Rozanski, G.J., Lipsius, S.L., Randall, W.C., Functional characteristics of sinoatrial and subsidiary pacemaker activity in the canine right atrium (1983) Circulation, 67, pp. 1378-1387 | |
| dc.description | Rubenstein, D.S., Fox, L.M., McNulty, J.A., Lipsius, S.L., Electrophysiology and ultrastructure of Eustachian ridge from cat right atrium: A comparison with S-A node (1987) J. Mol. Cell. Cardiol., 19, pp. 965-976 | |
| dc.description | Rubenstein, D.S., Lipsius, S.L., Mechanisms of automaticity in subsidiary pacemakers from cat right atrium (1989) Circ. Res., 64, pp. 648-657 | |
| dc.description | Satoh, H., Blatter, L.A., Bers, D.M., Effects of [Ca 2+];, SR Ca 2+ load and rest on Ca 2+ spark frequency in ventricular myocytes. Am (1997) J. Physiol., 272, pp. H657-H668. , (Heart Circ. Physiol. 41) | |
| dc.description | Spencer, L., Mörner, S.E.N.J., Noble, M.I.M., Seed, W.A., Influences of stimulation frequency and température on interval-force relationships in guinea-pig papillary muscles (1994) Acta Physiol. Scand., 150, pp. 11-20 | |
| dc.description | Varro, A., Negretti, N., Hester, S.B., Eisner, D.A., An estimate of the calcium content of the sarcoplasmic reticulum in rat ventricular myocytes (1993) Pflügers Arch., 423, pp. 158-160 | |
| dc.description | Wang, Y.G., Lipsius, S.L., A cellular mechanism contributing to postvagal tachycardia studies in isolated pacemaker cells from cat right atrium (1996) Circ. Res., 79, pp. 109-114 | |
| dc.description | Wier, W.G., Cytoplasmic calcium in mammalian ventricle: Dynamic control by cellular processes (1990) Annu. Rev. Physiol., 52, pp. 467-485 | |
| dc.description | Zhou, Z., Lipsius, S.L., Properties of the pacemaker current (If) in latent pacemaker cells isolated from cat right atrium (1992) J. Physiol. (Land.), 453, pp. 505-523 | |
| dc.description | Zhou, Z., Lipsius, S.L., Na +-Ca 2+ exchange current in latent pacemaker cells isolated from cat right atrium (1993) J. Physiol. (Land.), 466, pp. 263-285 | |
| dc.description | Zhou, Z., Lipsius, S.L., T-type calcium current in latent atrial pacemaker cells isolated from cat right atrium (1994) J. Mol. Cell. Cardiol., 26, pp. 1211-1219 | |
| dc.language | en | |
| dc.publisher | | |
| dc.relation | American Journal of Physiology - Heart and Circulatory Physiology | |
| dc.rights | fechado | |
| dc.source | Scopus | |
| dc.title | Diastolic Sr Ca Efflux In Atrial Pacemaker Cells And Ca-overloaded Myocytes | |
| dc.type | Artículos de revistas | |
