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Updated: Oct 8, 2026

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
[The blocking effects of six antiarrhythmic drugs on transient outward current in rat ventricular myocytes]
1Department of Pharmacology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050.
Abstract:
The effects of six antiarrhythmic drugs on transient outward current (Ito) in rat ventricular myocytes were examined by using the patch-clamp whole-cell recording technique. Quinidine, nifedipine, and imipramine resulted in a concentration-dependent inhibition of Ito with IC50s of 5.4, 10.9 and 6.0 mumol.L-1, respectively. All three agents produced a concentration-dependent increase in the rate of inactivation of Ito. Disopyramide, procainamide and E-4031 produced little inhibition of Ito even when present at 100 mumol.L-1. The results from this study show that quinidine, nifedipine and imipramine are potent inhibitors of Ito and that inhibition is mediated through preferential interaction with the open channel.
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