Inhibitory Effects of Bifemelane on Brain Ca^<2+> Channel Subtypes Expressed in Xenopus Oocytes

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Author(s)

Abstract

Effects of the cerebroprotective agent bifemelane on voltage-dependent Ca<SUP>2+</SUP> channel currents were evaluated in <I>Xenopus</I> oocytes expressing specific Ca<SUP>2+</SUP>-channel subtypes. Extracellular perfusion of bifemelane showed a dose-dependent blocking action on both N-type and Q-type Ca<SUP>2+</SUP> channels, but not on cardiac L-type Ca<SUP>2+</SUP> channels expressed in the oocytes, and the inhibitory action on Q-type current was stronger than that on N-type current. The time course of inhibition by bifemelane was comparatively slow; a 20-min perfusion with 1 μM bifemelane was required to reduce the amplitude of the Q-type current to 80% of the control level. When bifemelane was applied intracellularly, the potency and time-course of inhibition was equivalent to that caused by the perfusion of bifemelane. The bifemelane-induced inhibition was voltage-dependent but not use-dependent in Q-type channels since it was apparent at more depolarized potentials but not influenced by the interval of depolarization. These results suggest that bifemelane inhibits the opening of the specific Ca<SUP>2+</SUP> channels located at nerve terminals to suppress excessive neurotransmitter release from neurons in some pathophysiological conditions such as ischemia.

Journal

  • The Japanese Journal of Pharmacology

    The Japanese Journal of Pharmacology 78(1), 39-44, 1998-09

    The Japanese Pharmacological Society

References:  28

Cited by:  1

Codes

  • NII Article ID (NAID)
    10008193673
  • NII NACSIS-CAT ID (NCID)
    AA00691188
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    00215198
  • NDL Article ID
    4565701
  • NDL Source Classification
    ZS51(科学技術--薬学)
  • NDL Call No.
    Z53-D199
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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