Advertisement

Amino Acids

, Volume 9, Issue 3, pp 235–246 | Cite as

A dual action of taurine on the delayed rectifier K+ current in embryonic chick cardiomyocytes

  • H. Satoh
Article

Summary

Effects of taurine on the delayed rectifier K+ channel in isolated 10-day-old embryonic chick ventricular cardiomyocytes were examined at different intracellular Ca2+ concentrations ([Ca]i), using whole-cell voltage and current clamp techniques. Experiments were performed at room temperature (22°C). Test pulses were applied between -20 to +90m V from a holding potential of -40mV. When [Ca]i was pCa 7, addition of 10 and 20 mM taurine to the bath solution reduced the delayed rectifier K+ current (IK) at +90mV by 17.4 ± 2.8% (n = 5, P < 0.01) and 25.5 ± 2.6% (n = 5, P < 0.001), respectively. In contrast, when [Ca]i was pCa 10, IK at +90 mV was enhanced by 19.1 ± 3.1% (n = 7, P < 0.01) at 10mM taurine, and by 29.3 ± 2.4% (n = 7, P < 0.001) at 20mM taurine. The voltage of half-maximum activation (V1/2) was shifted in a hyperpolarizing direction; at pCa 7, the value was +0.2 ± 2.2mV (n = 5) in control and -10.6 ± 1.8mV (n = 5) in 20mM taurine. At pCa 10, the V1/2 value was +18.5 ± 4.6mV (n = 5) in control and +6.6 ± 5.2mV (n = 5) in taurine (20mM). Taurine decreased the action potential duration (APD) at pCa 10, but at pCa 7 did not affect it. In addition, taurine enhanced the transient outward current in a concentration-dependent manner. These results indicate that taurine modulates the delayed rectifier K+ channel, an effect dependent on [Ca]i and capable of regulating APD.

Keywords

Amino acids Taurine Delayed rectifier K+ channel Action potential duration Transient outward current Embryonic chick heart cells Whole-cell voltage and current clamps 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Benyajati S, Bay SM (1992) Sodium-taurine cotransport in reptilian renal brush-border membrane vesicles. Pflügers Arch 421: 168–175Google Scholar
  2. Carbone E, Swandulla D (1989) Neuronal calcium channels: kinetics, blockade and modulation. Prog Biophys Mol Biol 54: 31–58Google Scholar
  3. Carmeliet E, Saikawa T (1982) Shortening of the action potential and reduction of pacemaker activity by lidocainine, quinidine and procainamide in sheep cardiac Purkinje fibers: An effect on Na or K currents? Circ Res 50: 257–272Google Scholar
  4. Eckert R, Chad JE (1984) Inactivation of Ca channels. Prog Biophys Mol Biol 44: 215–267Google Scholar
  5. Fabiato A, Fabiato F (1979) Calcium programs for computing the composition of the solutions containing multiple metals and ligands used for experiments in skinned muscle cells. J Physiol (Lond) 75: 463–505Google Scholar
  6. Failli P, Fazzini A, Franconi F, Stendardi I, Giotti A (1992) Taurine antagonizes the increase in intracellular calcium concentration induced by α-adrenergic stimulation in freshly isolated guinea-pig cardiomyocytes. J Mol Cell Cardiol 24: 1253–1265Google Scholar
  7. Franconi F, Martini F, Stendari I, Matucci R, Zilleti L, Giotti A (1982) Effect of taurine on calcium level and contractility in guinea-pig ventricular strips. Biochem Pharmacol 31: 3181–3185Google Scholar
  8. Hagiwara N, Irisawa H, Kameyama M (1988) Contribution of two types of calcium currents to the pacemaker potentials of rabbit sino-atrial node cells. J Physiol (Lond) 395: 233–253Google Scholar
  9. Huxtable RJ, Sebring LA (1982) Cardiovascular actions of taurine. In: Kuriyama K, Huxtable RJ, Iwata H, Liss AR (eds) Sulfur amino acids: biochemical and clinical aspects. Biochem Clin Aspec, New York, pp 5–37Google Scholar
  10. Isenberg G (1975) Is potassium conductance of cardiac Purkinje fibres controlled by [Ca2+]i? Nature 253: 273–274Google Scholar
  11. Kass RS, Sanguinetti MC (1984) Inactivation of calcium channel current in the calf cardiac Purkinje fiber. Evidence for voltage- and calcium-mediated mechanisms. J Gen Physiol 84: 705–726Google Scholar
  12. Kramer JH, Chovan JP, Schaffer SW (1981) Effect of taurine on calcium paradox and ischemic heart failure. Am J Physiol 240: H238–H246Google Scholar
  13. Lee KS, Marban E, Tsien RW (1985) Inactivation of calcium channels in mammalian heart cells: joint dependence on membrane potential and intracellular calcium. J Physiol (Lond) 364: 395–411Google Scholar
  14. Lombardini JB (1980) Effect of ischemia on taurine levels. In: Cavallini D, Gaull GE, Zappia V (eds) Natural sulfur compounds. Plenum Press, New York, pp 255–257Google Scholar
  15. Lombardini JB (1992) Effects of taurine on protein phosphorylation in mammalian tissues. In: Lombardini B, Schaffer S, Azuma J (eds) Taurine: nutritional value and mechanism of actions. Plenum Press, New York, pp 309–318Google Scholar
  16. Lombardini JB, Bricker DL (1981) Effects of cardiovascular surgery on blood concentrations of taurine and amino acids. Proc Soc Exp Biol Med 167: 498–505Google Scholar
  17. McAllister RE, Noble D, Tsien RW (1975) Reconstruction of the electrical activity of cardiac Purkinje fibers. J Physiol (Lond) 251: 1–59Google Scholar
  18. Meech RW (1974) The sensitivity of Helix aspersa neurones to injected calcium ions. J Physiol (Lond) 237: 259–277Google Scholar
  19. Satin LS, Cook DL (1989) Calcium current inactivation in insulin secreting cells is mediated by calcium influx and membrane depolarization. Pflügers Arch 414: 1–10Google Scholar
  20. Satoh H (1993a) Electrophysiological actions of adenosine and aminophylline in spontaneously beating and voltage-clamped rabbit sino-atrial node preparations. Naunyn-Schmiedebergs Arch Pharmacol 347: 197–204Google Scholar
  21. Satoh H (1993b) Arrhythmogenic actions of class III antiarrhythmic drugs in spontaneously beating sino-atrial node preparations. Gen Pharmacol 24: 1435–1442Google Scholar
  22. Satoh H (1994) Regulation of the action potential duration by taurine in guinea-pig ventricular muscle. Gen Pharmacol 25: 47–52Google Scholar
  23. Satoh H, Hashimoto K (1988) On electrophysiological responses to phorbol esters which stimulate protein kinase C in rabbit sino-atrial node cells. Naunyn-Schmiedebergs Arch Pharmacol 337: 308–315Google Scholar
  24. Satoh H, Sperelakis N (1991) Identification of the hyperpolarization-activated inward current in young emb yonic chick heart myocytes. J Develop Physiol 15: 247–252Google Scholar
  25. Satoh H, Sperelakis N (1992) Taurine inhibition of Na+ current in embryonic chick ventricular myocytes. Eur J Pharmacol 218: 83–89Google Scholar
  26. Satoh H, Sperelakis N (1993) Effects of taurine on Ca2+ currents in young embryonic chick cardiomyocytes. Eur J Pharmacol 231: 443–449Google Scholar
  27. Satoh H, Tsuchida K, Hashimoto K (1989) Electrophysiological actions of A23187 and X-537A in spontaneously beating and in voltage-clamped rabbit sino-atrial node preparations. Naunyn-Schmiedebergs Arch Pharmacol 339: 320–326Google Scholar
  28. Sawamura A, Sperelakis N, Azuma J (1986) Protective effect of taurine against decline of cardiac slow action potentials during hypoxia. Eur J Pharmacol 120: 235–239Google Scholar
  29. Sawamura A, Sada H, Azuma J, Kishimoto S, Sperelakis N (1990) Taurine modulates ion influx through cardiac Ca2+ channels. Cell Calcium 11: 251–259Google Scholar
  30. Schaffer SW, Allo S, Mozaffari M (1987) Potentiation of myocardial ischemic injury by drug-induced taurine depletion. In: Huxtable RJ, Franconi F, Giotti A (eds) The biology of taurine. Plenum Press, New York, pp 151–158Google Scholar
  31. Schaffer SW, Kramer J, Chovan JP (1980) Regulation of calcium homeostasis in the heart by taurine. Fed Proc 39: 2691–2694Google Scholar
  32. Segawa T, Nomura Y, Shimazaki I (1985) Possible involvement of calmoduline in modulatory role of taurine in rat cerebralβ-adrenergic neurons. In: Oja SS, Ahtee L, Kontro P, Paasonen MK (eds) Taurine: biological actions and clinical perspectives. Alan R. Liss, New York, pp 321–330Google Scholar
  33. Sperelakis N, Satoh H (1993) Taurine effects on ion channels of cardiac muscle. In: Noble D, Earm YE (eds) Ionic channels and effect of taurine on the heart. Kluwer Academic Publ, Boston, pp 93–118Google Scholar
  34. Sperelakis N, Yamamoto T, Bkaily G, Sada H, Sawamura A, Azuma J (1988) Taurine effects on action potentials and ionic currents in chick myocardial cells. In: Iwata H, Lombardini JB, Segawa T (eds) Taurine and the heart. Kluwer Academic Publ, Boston, pp 1–19Google Scholar
  35. Sperelakis N, Satoh H, Bkaily G (1992) Taurine's effects on ionic currents in myocardial cells. In: Lombardini B, Schaffer S, Azuma J (eds) Taurine: nutritional value and mechanism of actions. Plenum Press, New York, pp 129–143Google Scholar
  36. Suleiman M-S, Rodrigo GC, Chapman RA (1992) Interdependence of intracellular taurine and sodium in guinea pig heart. Cardiovasc Res 26: 897–905Google Scholar
  37. Tsien RY, Rink TJ (1980) Neutral carrier ion-selective microelectrodes for measurements of intracellular free calcium. Biochim Biophys Acta 599: 623–638Google Scholar

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • H. Satoh
    • 1
  1. 1.Department of PharmacologyNara Medical UniversityKashihara, NaraJapan

Personalised recommendations