Effect of antiarrhythmic drugs on choline uptake in cardiac cells in culture.
OBJECTIVE
The aim was to examine the effect on choline uptake of various antiarrhythmic drugs: lignocaine, tocainide, encainide, flecainide, propafenone, procainamide, N-acetylprocainamide, bretylium, and amiodarone.


METHODS
Cardiac ventricular myocytes from 7 d old chick embryos were exposed in culture to these drugs, at concentrations ranging from 10(-6) to 10(-4) M, for 24 h. Myocyte choline uptake was assessed by the addition of methyl [3H] choline to media. After 120 min, media were removed, the cells were harvested, and intracellular [3H] actively was counted.


RESULTS
Lignocaine and tocainide produced a significant (p less than 0.05) dose dependent increase in intracellular [methyl 3H] choline. Encainide produced a small increase and flecainide a small decrease in choline, neither of which was dose dependent. Propafenone significantly (p less than 0.05) altered choline uptake: at 10(-6) M and 10(-5) M choline uptake was increased and at 10(-4) M it was decreased. Amiodarone produced a marked and significant (p less than 0.05) dose dependent reduction in choline uptake. Bretylium, procainamide, and N-acetylprocainamide did not alter myocyte choline.


CONCLUSIONS
Choline incorporation into cardiac myocyte is altered by some antiarrhythmic drugs, suggesting this may be part of their antiarrhythmic properties.
Rabkin
S W
SW
Cardiovascular Research Laboratories, University Hospital (Shaughnessy), University of British Columbia, Vancouver, Canada.
D000638:Amiodarone / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D002642:Chick Embryo; D002794:Choline / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D016700:Encainide / Q000494:pharmacology; D005424:Flecainide / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D008012:Lidocaine / Q000494:pharmacology; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011405:Propafenone / Q000494:pharmacology; D016677:Tocainide / Q000494:pharmacology
D000889:Anti-Arrhythmia Agents; D016677:Tocainide; D011405:Propafenone; D008012:Lidocaine; D005424:Flecainide; D000638:Amiodarone; D002794:Choline; D016700:Encainide