Effects of pirmenol HCl on electrophysiologic properties of cardiac Purkinje fibers
Abstract
We studied the effects of pirmenol hydrochloride (CI 845), cis-(+/-)-alpha-[3-(2,6-dimethyl-1-piperidinyl)propyl]-alpha-phenyl-2-pyridinemethanol monohydrochloride, on the electrophysiologic properties of canine cardiac Purkinje fibers having normal (fast response) action potentials. CI 845 greater than or equal to 1 X 10(-6) M depressed both maximum upstroke velocity of phase 0 and automaticity. CI 845 greater than or equal to 1 X 10(-5) M significantly decreased action potential amplitude and duration measured at 50% repolarization and prolonged action potential duration measured at full repolarization. In addition, this concentration depressed membrane responsiveness and prolonged the effective refractory period and conduction time. All changes were reversible following superfusion with drug-free Tyrode solution. Increasing extracellular potassium ([K+]0) from 4 mM to 6 mM did not potentiate the CI 845-induced changes. CI 845 1 X 10(-5) M decreased automaticity of slow response action potentials studied in a Na+-free solution but had no effect on the action potential characteristics of these spontaneously discharging fibers. In blood superfusion studies, plasma levels of 0.1--3.0 micrograms/ml CI 845 affected the action pote...Continue Reading
References
Citations
Related Concepts
Related Feeds
Cardiac Conduction System
The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.