PT  - JOURNAL ARTICLE
AU  - V Elharrar
AU  - J C Bailey
AU  - D A Lathrop
AU  - D P Zipes
TI  - Effects of aprindine HCl on slow channel action potentials and transient depolarizations in canine Purkinje fibers.
DP  - 1978 May 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 410--417
VI  - 205
IP  - 2
4099  - http://jpet.aspetjournals.org/content/205/2/410.short
4100  - http://jpet.aspetjournals.org/content/205/2/410.full
SO  - J Pharmacol Exp Ther1978 May 01; 205
AB  - The electrophysiologic effects of aprindine hydrochloride were studied on normal Purkinje fibers, on Purkinje fibers superfused with Tyrode's solution containing 22 mM KCl and isoproterenol (1 X 10(-5) M) and on transient depolarizations induced by exposure to acetylstrophanthidin (1.7--2 X 10(-7) M). Aprindine (3 X 10(-6) M) significantly reduces the action potential amplitude and dV/dtmax and shortens the action potential duration but does not alter the resting membrane potential. Transient depolarizations were suppressed by aprindine at a dose of 2 X 10(-6) M. Isoproterenol (1 X 10(-5) M) failed to restore the transient depolarizations after suppression with aprindine. Slow responses induced in K-depolarized, isoproterenol-treated fibers were unchanged by aprindine (3 X 10(-6)-1 X 10(-5) M) in the presence as well as in the absence of acetylstrophanthidin. These experiments suggest that aprindine does not have slow channel blocking properties and that an inward current through the slow channel cannot be considered as the sole basis of the digitalis-induced transient depolarization.