Effects of ajmaline on non-sodium ionic currents in guinea pig ventricular myocytes. 1995

K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
First Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.

The lack of currently available data stimulated us to investigate the electrophysiological effects of ajmaline, a classical class Ia antiarrhythmic agent, on various currents responsible for the action potential plateau and repolarization phases. The whole cell patch clamp recording technique was applied to guinea pig ventricular myocytes. Ajmaline suppressed the Ca2+ current (Ica) in a dose-dependent manner (Kd = 1.2 x 10(-5) M) without affecting the steady-state inactivation kinetics and the voltage dependency of the current-voltage relationship. Ajmaline inhibited the inward portion of the inward rectifying K+ current (IKl). Ajmaline decreased the delayed rectifier K+ current (IK) without altering the activation or deactivation time courses. All these inhibitory effects of ajmaline prolonged the action potential duration in a dose dependent manner. The inhibitory actions of ajmaline on the action potential upstroke and various currents responsible for the plateau and repolarization may contribute to the observed suppression of depolarization-induced abnormal automaticities by this agent.

UI MeSH Term Description Entries
D007477 Ions An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
D009206 Myocardium The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow. Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D011188 Potassium An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004553 Electric Conductivity The ability of a substrate to allow the passage of ELECTRONS. Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D006168 Guinea Pigs A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research. Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000200 Action Potentials Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli. Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000404 Ajmaline An alkaloid found in the root of RAUWOLFIA SERPENTINA, among other plant sources. It is a class 1-A antiarrhythmic agent that apparently acts by changing the shape and threshold of cardiac action potentials. Ajmaline Hydrochloride,Aritmina,Cardiorythmine,Gilurtymal,Rauverid,Serenol,Tachmalin,Wolfina
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D000889 Anti-Arrhythmia Agents Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade. Anti-Arrhythmia Agent,Anti-Arrhythmia Drug,Anti-Arrhythmic,Antiarrhythmia Agent,Antiarrhythmia Drug,Antiarrhythmic Drug,Antifibrillatory Agent,Antifibrillatory Agents,Cardiac Depressant,Cardiac Depressants,Myocardial Depressant,Myocardial Depressants,Anti-Arrhythmia Drugs,Anti-Arrhythmics,Antiarrhythmia Agents,Antiarrhythmia Drugs,Antiarrhythmic Drugs,Agent, Anti-Arrhythmia,Agent, Antiarrhythmia,Agent, Antifibrillatory,Agents, Anti-Arrhythmia,Agents, Antiarrhythmia,Agents, Antifibrillatory,Anti Arrhythmia Agent,Anti Arrhythmia Agents,Anti Arrhythmia Drug,Anti Arrhythmia Drugs,Anti Arrhythmic,Anti Arrhythmics,Depressant, Cardiac,Depressant, Myocardial,Depressants, Cardiac,Depressants, Myocardial,Drug, Anti-Arrhythmia,Drug, Antiarrhythmia,Drug, Antiarrhythmic,Drugs, Anti-Arrhythmia,Drugs, Antiarrhythmia,Drugs, Antiarrhythmic

Related Publications

K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
June 2007, Acta pharmacologica Sinica,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
April 2001, Yao xue xue bao = Acta pharmaceutica Sinica,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
April 1989, Acta anaesthesiologica Scandinavica,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
January 2002, Acta pharmacologica Sinica,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
January 2013, Biological & pharmaceutical bulletin,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
January 1998, Journal of cardiovascular pharmacology and therapeutics,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
April 1999, Journal of molecular and cellular cardiology,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
October 1986, Journal of molecular and cellular cardiology,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
November 1988, European journal of pharmacology,
K Enomoto, and M Imoto, and R Nagashima, and T Kaneko, and T Maruyama, and Y Kaji, and Y Tsuda, and S Kanaya, and T Fujino, and Y Niho
August 2000, British journal of pharmacology,
Copied contents to your clipboard!