Inhibition of the slow inward current and the time-dependent outward current of mammalian ventricular muscle by gentamicin

N. Hino, R. Ochi, T. Yanagisawa

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

The aminoglycoside antibiotic, gentamicin (GM), depressed the plateau phase and shortened the duration of the action potential in guinea pig papillary muscle. Its effect on the membrane currents was studied by a single sucrose gap voltage clamp method. The slow inward current (is) was remarkably diminished by GM with little change in its time course, in the voltage-dependency of the steady-state inactivation and activation or in its reversal potential. The maximal amplitude of is, obtained by subtracting the Co2+-resistant current, was reduced to 57% by 0.1 mmol/l GM and almost reduced to zero by 1 mmol/l GM. The efficacy of GM in inhibiting is was reduced by increasing the external Ca2+ concentration from 1.8 to 5.4 or 10.8 mmol/l, but not by the application of adrenaline. The time-dependent outward current (iK) was also decreased by GM but only at higher concentrations. It is proposed that the depressant action of GM on is was due to a blockade of slow channels, whereby GM may have dislocated Ca from the binding sites at slow channels on the external surface of the membrane.

Original languageEnglish
Pages (from-to)243-249
Number of pages7
JournalPflügers Archiv European Journal of Physiology
Volume394
Issue number3
DOIs
Publication statusPublished - 1982 Sep 1

Keywords

  • Calcium
  • Gentamicin
  • Papillary muscle
  • Slow inward current
  • Time-dependent outward current

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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