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Taurine 3 pp 137-143 | Cite as

Effects of Taurine on Signal Transduction Steps Induced during Hypertrophy of Rat Heart Myocytes

  • M. R. Rao
  • L. Tao
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 442)

Abstract

Angiotensin II plays an important role in the development of cardiac hypertrophy. One factor thought to contribute to the trophic activity of angiotensin II in fibroblasts is the elevation in [Ca2+]i. Although this theory has received considerable support in cardiac fibroblasts, it is much more controversial in cardiac myocytes. Therefore, the aim of this report was to examine the effect of several Ca2+ modulators on protein synthesis in neonatal cardiac myocytes. We found that angiotensin II increased both [Ca2+]i and the rate of protein synthesis in isolated myocytes. Both effects were blocked by nifedipine, but only the angiotensin II-mediated increase in [Ca2+]i was inhibited by taurine in a dose-dependent manner. These data support the notion that Ca2+ plays only a permissive role in angiotensin II-mediated stimulation of protein synthesis. By contrast, the ability of taurine to attenuate the positive chronotropic effect, the prolongation of the action potential and the proarrhythmic activity of angiotensin II appear to be linked directly to changes in [Ca2+]i. We conclude that taurine reverses these actions of angiotensin II by altering Ca2+ flux across the cell membrane.

Keywords

Cardiac Hypertrophy Cardiac Myocytes Cardiac Fibroblast Action Potential Amplitude Renin Gene 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Baker, K.M. and Aceto, J.F., 1990, Angiotensin II stimulation of protein synthesis and cell growth in chick heart cells, Am. J. Physiol., 259:H610–H618.PubMedGoogle Scholar
  2. 2.
    Ballard-Croft, C., Mozaffari, M.S., Azuma, J., and Schaffer, S., 1997, Interaction between taurine and angiotensin II: modulation of calcium transport and myocardial contractile function, Amino Acids, 13:105–114.CrossRefGoogle Scholar
  3. 3.
    Boer, P.H., Ruzicka, M., Lear, W., Harmsen, E., Rosenthal, J., and Leenen, F.H.H., 1994, Stretchmediated activation of cardiac renin gene, Am. J. Physiol. 267:H1630–H1636.PubMedGoogle Scholar
  4. 4.
    Booz, G.W., Dostal, D.E., Singer, H.A., and Baker, K.M., 1994, Involvement of protein kinase C and Ca2+ in angiotensin II-induced mitogenesis of cardiac fibroblasts, Am. J. Physiol. 267:C1308–1318.PubMedGoogle Scholar
  5. 5.
    Kinugawa, K-I, Takahashi, T., Kohmoto, O., Yao, A., Ikenouchi, H., and Serizawa, T., 1995, Ca2+-growth coupling in angiotensin II-induced hypertrophy in cultured rat cardiac cells, Cardiovasc. Res., 30:419–431.PubMedGoogle Scholar
  6. 6.
    Neyses, L., Nouskas, J., Luyken, J., Fronhoffs, S., Oberdorf, S., Pfeifer, U., Williams, R.S., Sukhatme, V.P., and Vetter, H., 1993, Induction of immediate-early genes by angiotensin II and endothelin-1 in adult rat cardiomyocytes, J. Hypertension 11:927–934.CrossRefGoogle Scholar
  7. 7.
    Nickenig, G., Laufs, U., Schnabel, P., Knorr, A., Paul, M and Bohm, M., 1997, Down-regulation of aortic and cardiac AT1 receptor gene expression in transgenic (mRen-2) 27 rats, Br. J. Pharmacol., 121:134–140.PubMedCrossRefGoogle Scholar
  8. 8.
    Passier, R.C.J.J., Smits, J.F.M., Verluyten, M.J.A., and Daemen, M.J.A.P., 1996, Expression and localization of renin and angiotensinogen in rat heart after myocardial infarction, Am. J. Physiol. 271:H1040–1048.PubMedGoogle Scholar
  9. 9.
    Sadoshima, J. and Izumo, S., 1995, Rapamycin selectively inhibits angiotensin II-induced increase in protein synthesis in cardiac myocytes in vitro, Circ. Res., 77:1040–1052.PubMedCrossRefGoogle Scholar
  10. 10.
    Sadoshima, J., Qui, Z., Morgan, J.P., and Izumo, S., 1995, Angiotensin II and other hypertrophic stimuli mediated by G protein-coupled receptors activate tyrosine kinase, mitogen-activated protein kinase and 90-kD S6 kinase in cardiac myocytes, Circ. Res., 76:1–15.PubMedCrossRefGoogle Scholar
  11. 11.
    Sperelakis, N., Katsube, Y., and Kusaka, M., 1996, Some actions of taurine on ionic current of myocardial cells and myometrial cells, in “Taurine 2: Basic and Clinical Aspects”, Huxtable, R.J., Azuma, J., Kuriyama, K., Nakagawa, M., and Baba, A., eds., Plenum Press, New York and London, pp. 275–284.Google Scholar
  12. 12.
    Takahashi, K., Hashimoto, H., Baba, A., Schaffer, S.W., and Azuma, J., 1996, in “Taurine 2: Basic and Clinical Aspects”, Huxtable, R.J., Azuma, J., Kuriyama, K., Nakagawa, M. and Baba, A., eds., Plenum Press, New York and London, pp. 297–304.Google Scholar
  13. 13.
    Takano, H., Komuro, I., Zou, Y., Kudoh, S., Yamazaki, T., and Yazaki, Y., 1996, Activation of p70 S6 protein kinase is necessary for angiotensin II-induced hypertrophy in neonatal rat cardiac myocytes, FEBS Lett., 379:255–259.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • M. R. Rao
    • 1
  • L. Tao
    • 1
  1. 1.Department of Cardiovascular PharmacologyNanjing Medical UniversityNanjingChina

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