title: Inhibition by amiodarone of slow response action potentials and contraction in guinea pig ventricular muscle.
abstract: 1. Effects of an antiarrhythmic agent, amiodarone (AM), on slow response action potentials and contraction of guinea pig ventricular muscle were examined. 2. AM (4.4 x 10(-5) M, 1.1 x 10(-4) M) significantly inhibited the maximum upstroke velocity of slow response action potentials and contraction. 3. As for action potential duration (APD), higher concentration (1.1 x 10(-4) M) of AM significantly shortened the APD, while low concentration (4.4 x 10(-5) M) had little effect on it. 4. These findings strongly suggest that AM blocks slow inward current inflow via Ca2+ channels in the ventricular muscle.
authors.affiliation: Department of Medicine, Northwestern University Medical School, Chicago, IL 60611.
authors.forename: M
authors.initials: M
authors.lastname: Aomine
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000638:Amiodarone / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D006168:Guinea Pigs; D007700:Kinetics; D009200:Myocardial Contraction / Q000187:drug effects*
chemical_list: D000638:Amiodarone; D002118:Calcium