Effects of Ajmaline on Non-sodium Ionic Currents in Guinea Pig Ventricular Myocytes
| Autor: | Toru Maruyama, Masahiro Imoto, Shozo Kanaya, Yoshiyuki Niho, Ryuichi Nagashima, Takehiko Fujino, Yoshikazu Kaji, Takeo Kaneko, Katsuaki Enomoto, Yasuo Tsuda |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
medicine.medical_specialty
Guinea Pigs Action Potentials chemistry.chemical_element Calcium Inhibitory postsynaptic potential Guinea pig Internal medicine medicine Animals Ventricular Function Myocyte Repolarization Patch clamp Ions Ajmaline Myocardium Electric Conductivity Electrophysiology Endocrinology chemistry Potassium Biophysics Cardiology and Cardiovascular Medicine Anti-Arrhythmia Agents medicine.drug |
| Zdroj: | Japanese Heart Journal. 36:465-476 |
| ISSN: | 1348-673X 0021-4868 |
| DOI: | 10.1536/ihj.36.465 |
| Popis: | 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 Ca 2+ current (I Ca ) in a dose-dependent manner (K d = 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 (I K1 ). Ajmaline decreased the delayed rectifier K + current (I K ) 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. (Jpn Heart J 36 : 465-476, 1995) |
| Databáze: | OpenAIRE |
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