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ISSN 2522-9028 (Print)
ISSN 2522-9036 (Online)

Fiziologichnyi Zhurnal

is a scientific journal issued by the

Bogomoletz Institute of Physiology
National Academy of Sciences of Ukraine

Editor: V.F. Sagach

The journal was founded in 1955 as
1955 – 1977 "Fiziolohichnyi zhurnal" (ISSN 0015 – 3311)
1978 – 1993 "Fiziologicheskii zhurnal" (ISSN 0201 – 8489)
1994 – 2016 "Fiziolohichnyi zhurnal" (ISSN 0201 – 8489)
2017 – "Fiziolohichnyi zhurnal" (ISSN 2522-9028)

Fiziol. Zh. 2001; 47(1): 39-45

Mechanisms of action of hypersodium mediumon contractile activity of isolated rat heart

V. V. Alabovsky, E. J. Cragoe, A. A. Winokurov

    Department of Biochemistry Voronezh State Medical Academy, Russia


V. V. Alabovsky, E. J. Cragoe, A. A. Winokurov MECHANISMS OF ACTION OF HYPERSODIUM MEDIUM ON CONTRACTILE ACTIVITY OF ISOLATED RAT HEART Despite the high efficiency of elevated concentrations of sodium ions during myocardial ischemia and calcium paradox, the molecular mechanism of action of hypersodium media on heart contractions remains unknown. The purpose of the investigation was to study mechanisms by which raised concentrations of sodium ions alter cardiac contractility. Subsequent to initially developed reduced pressure in the left ventricle, elevated concentrations of sodium ions (200 mM instead of 140 mM NaCl, 3 mM KCl) produced an increased force of contractions of about 50%. The first stage of decrease in developed pressure did not relate to elevated tonicity of extracellular ionic millieu because lithium chloride (60 mM) did not produce the same effect. This action of elevated concentrations of sodium ions has been shown to be independent of blockers of ion-transporting systems (caffeine, verapamile, ethmozine, HMA or lidocaine). Raising the contractions by elevating the concentration of sodium ions (second stage) has been shown to be susceptible to sodium channel blockers (6-IA,benzamil, of phenamil) and to cafeine. Decreasing of potassium concentration (from 3 mM to 1—2 mM amplified, and increasing of K+ level (from 3 mM to 6 mM) attenuated the positive inotropic action of the elevated concentration of sodium ions. The positive inotropic effect due to elevated concentrations of sodium ions remains even after heart arrest by high concentrations of verapamile (2 mcM). Lithium chloride (60 mM) failed to elevate left ventricle developed pressure which was raised by elevated concentrations of sodium ions. These data suggest that the elevated concentration of sodium ions could effect Na+/Ca2+ exchange and provoke Ca2+ release from sarcoplasmic reticulum by changing the sodium gradient and resulting in Ca2+ entry via Na+/Ca2+ exchange. These observations are consistent with the hypothesis of Leblanc N., Hume J.R. (1990) regarding sodium-induced calcium ion release from sarcoplasmic reticulum. Department of Biochemistry Voronezh State Medical Academy, Russia


  2. Алабовский В.В. Энергозависимые процессы миокарда при изменении внеклеточной концентрации натрия и активировании Na—Са-обмена: Автореф. дис. … д-ра мед. наук. — М.: Университет Дружбы народов, 1986. — С. 63.
  3. Алабовский В.В., Винокуров А.А., Кобрин В.И., Олейников О.Д. Предупреждение искусственным увеличением трансмембранного градиента натрия реперфузионных повреждений сердца при «кальциевом парадоксе» и постишемической реперфузии // Физиол. журн. — 1991. — 37, №3. — С.25-30.
  4. Кобрин В.И., Алабовский В.В., Алипов Н.Н., Олейников О.Д. Электрическая активность клеток сердца и сократительная активность миокарда при изменении внеклеточной концентрации натрия // Физиол. журн. СССР. — 1988. — 24, № 9. —С.1257-1262.
  5. Сhapman R.A. Control of cardiac contractility at the cellular level // Amer. J. Physiol.—1983. — 245. — P. H535-H552.
  6. Gilbert J.C., Shirayama T., Pappano A.J. Inositol triphosphate promotes Na-Ca exchange current by releasing calcium from sarcoplasmic reticulum in cardiac myocytes //Circulat. Res. — 1991. — 91. — P. 1632-1639.
  7. Frantisek K., Cole W., Ostadal B., Dhalla N.S. Transient inotropic effect of low extracellular sodium in perfused rat heart // Amer. J. Physiol. — 1990. — 259.—P.H712-H719.
  8. Leblanc N., Hume J.R. Sodium current — induced release of calcium from cardiac sarcoplasmic reticulum // Science. — 1990. — 248, N 4953. — P. 372-375.
  9. Mclaghlin A., Eng W.K., Vaio G. et al. Dimethonium, a divalent cation that exerts only a screening effect on the electrostatic potential adjacent to negatively charged phospholipid bilayer membranes // J.Membr. Biol. — 1983. — 76. — P. 183-193.
  10. 9. Miura Y., Kimura J. Sodium- calcium exchange current. Dependence on internal Ca and Na and competitive binding of external Na and Ca // J. Gen. Physiol. — 1989. — 93. — P. 1129-1145.
  11. 10. Nathan R.D. Negative surfase charge: it’s identification and regulation of cardiac electrogenesis. In: Carduac Muscle. The regulation of excitation and contraction. — N.-Y.: Academ. Press, 1986. — P. 255-298.
  12. Sheu S.S., Blaustein M.P. Sodium- Salcium exchange and control of Cell Calcium and contractility in cardiac and vascular smooth muscles. In: The Heart and Cardiovascular system. N.-Y.: Raven Press, 1992. — P. 903-942.
  13. Tillish J.H., Langer G.A. Myocardial mechanical responses and ionic exchange in elevated sodium perfusate // Circulat.Res. — 1974. — 34. — P. 211-213.

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