PMID: 9550298Apr 29, 1998Paper

Effect of disopyramide on potassium currents in rabbit ventricular myocytes

Naunyn-Schmiedeberg's Archives of Pharmacology
L VirágJ G Papp

Abstract

The effects of disopyramide (1-30 microM) on the 4-aminopyridine sensitive transient outward current (I(to)), on the rapid component of the delayed rectifier potassium current (I(Kr)) and on the inward rectifier potassium current (I(kl)) were studied in single rabbit ventricular myocytes at 35 degrees C by applying the whole-cell configuration of the patch clamp technique. Disopyramide significantly decreased the amplitude of I(to) (from 1510 +/- 122 pA at control to 1015 +/- 21 pA after 30 microM disopyramide at +50 mV; n = 5). This effect was not voltage- or use-dependent. Disopyramide (10 microM) influenced neither the recovery from inactivation of I(to) nor the steady-state inactivation curve. The drug dose dependently decreased the time constant of the fast component of the decay of I(to) (tau(f) = 6.41 +/- 0.25 ms, n = 24 for control; and 2.20 +/- 0.38 ms, n = 5 after 30 microM disopyramide at +50 mV). The fractional block caused by 30 microM disopyramide as a function of time was well fitted by a single exponential function with time constant of 1.48 +/- 0.18 ms (n = 5), most likely reflecting the binding kinetics of the drug to the open channel. The offset kinetics of the drug was estimated by using a double-pulse proto...Continue Reading

Citations

Oct 7, 2000·Clinical and Experimental Pharmacology & Physiology·H J Witchel, J C Hancox
Feb 13, 2001·Biochemical and Biophysical Research Communications·A A PaulJ C Hancox
Aug 9, 2003·The Journal of Pharmacy and Pharmacology·Erika HanadaTatsuji Iga
Mar 18, 2011·British Journal of Pharmacology·L VirágA Varró
Jun 14, 2003·Biochemical and Biophysical Research Communications·John M RidleyJules C Hancox
Oct 13, 2011·Journal of Molecular and Cellular Cardiology·Aziza El HarchiJules C Hancox
Sep 27, 2008·Journal of Pharmacological Sciences·Iván A AréchigaRicardo A Navarro-Polanco
Mar 26, 2003·Journal of Cardiovascular Pharmacology and Therapeutics·Norbert IostJulius Gy Papp
Sep 13, 2002·Circulation Journal : Official Journal of the Japanese Circulation Society·Hiroshi YoshidaKeitaro Hashimoto
Oct 17, 2001·Journal of Cardiovascular Pharmacology·T YangD M Roden

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