Effects of Ajmaline on Non-sodium Ionic Currents in Guinea Pig Ventricular Myocytes

Katsuaki Enomoto, Masahiro Imoto, Ryuichi Nagashima, Takeo Kaneko, Toru Maruyama, Yoshikazu Kaji, Yasuo Tsuda, Yoshiyuki Niho, Shozo Kanaya, Takehiko Fujino

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The lack of currently available data stimulated us to investigate the electrophysiological effects of ajmaline, a classical class la 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 × 10-5 M) without affecting the steady-state inacti-vation kinetics and the voltage dependency of die current-voltage relationship. Ajmaline inhibited the inward portion of the inward rectifying K+ current (IKI). 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 die 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).

Original languageEnglish
Pages (from-to)465-476
Number of pages12
Journaljapanese heart journal
Volume36
Issue number4
DOIs
Publication statusPublished - Jan 1 1995

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Ajmaline
Muscle Cells
Guinea Pigs
Action Potentials
Patch-Clamp Techniques

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine

Cite this

Enomoto, K., Imoto, M., Nagashima, R., Kaneko, T., Maruyama, T., Kaji, Y., ... Fujino, T. (1995). Effects of Ajmaline on Non-sodium Ionic Currents in Guinea Pig Ventricular Myocytes. japanese heart journal, 36(4), 465-476. https://doi.org/10.1536/ihj.36.465

Effects of Ajmaline on Non-sodium Ionic Currents in Guinea Pig Ventricular Myocytes. / Enomoto, Katsuaki; Imoto, Masahiro; Nagashima, Ryuichi; Kaneko, Takeo; Maruyama, Toru; Kaji, Yoshikazu; Tsuda, Yasuo; Niho, Yoshiyuki; Kanaya, Shozo; Fujino, Takehiko.

In: japanese heart journal, Vol. 36, No. 4, 01.01.1995, p. 465-476.

Research output: Contribution to journalArticle

Enomoto, K, Imoto, M, Nagashima, R, Kaneko, T, Maruyama, T, Kaji, Y, Tsuda, Y, Niho, Y, Kanaya, S & Fujino, T 1995, 'Effects of Ajmaline on Non-sodium Ionic Currents in Guinea Pig Ventricular Myocytes', japanese heart journal, vol. 36, no. 4, pp. 465-476. https://doi.org/10.1536/ihj.36.465
Enomoto, Katsuaki ; Imoto, Masahiro ; Nagashima, Ryuichi ; Kaneko, Takeo ; Maruyama, Toru ; Kaji, Yoshikazu ; Tsuda, Yasuo ; Niho, Yoshiyuki ; Kanaya, Shozo ; Fujino, Takehiko. / Effects of Ajmaline on Non-sodium Ionic Currents in Guinea Pig Ventricular Myocytes. In: japanese heart journal. 1995 ; Vol. 36, No. 4. pp. 465-476.
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