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Journal of Anesthesia

, Volume 15, Issue 3, pp 149–153 | Cite as

Effects of ketamine on voltage-dependent calcium currents and membrane potentials in single bullfrog atrial cells

  • Noboru Hatakeyama
  • Mitsuaki Yamazaki
  • Nobuko Shibuya
  • Shigeo Yamamura
  • Yasunori Momose

Abstract

Purpose. This study was undertaken to assess the effect of ketamine on L-type calcium channel current (ICa) and membrane action potential in the bullfrog single atrial myocyte.

Methods. Bullfrog single atrial myocytes were prepared by enzymatic dispersion. Whole-cell voltage-clamp technique and current clamp technique were used to monitor ICa, membrane resting potential, and action potential.

Results. Ketamine (10−5–10−3 M) showed dose-dependent inhibition of ICa in a reversible manner. The 50% inhibitory concentration (IC50) of ketamine on ICa was estimated to be 0.92 × 10−5 M. Use-dependent block of ICa was not observed. The resting membrane potential was depolarized at a high concentration (10−4 M) of ketamine. Reduction of the plateau phase and prolonged duration of the action potential were observed in the presence of a high concentration of ketamine (10−4 M).

Conclusion. Ketamine has an inhibitory effect on ICa in the bullfrog single atrial myocyte, and a high dose (10−4 M) of ketamine prolonges the duration of the action potential. The mechanism of inhibition of ICa seems to be a direct effect on the L-type calcium channel, not like an open channel blocker.

Key words Ketamine Calcium current Action potential Atrial cell Bullfrog 

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Copyright information

© Japan Society of Anesthesiology 2001

Authors and Affiliations

  • Noboru Hatakeyama
    • 1
  • Mitsuaki Yamazaki
    • 1
  • Nobuko Shibuya
    • 1
  • Shigeo Yamamura
    • 2
  • Yasunori Momose
    • 2
  1. 1.Department of Anesthesiology, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-0194, JapanJP
  2. 2.Faculty of Medicine and Department of Clinical Pharmacy, Toho University, School of Pharmaceutical Sciences, Funabashi, JapanJP

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