Actions of mibefradil, efonidipine and nifedipine block of recombinant T- and L-type Ca channels with distinct inhibitory mechanisms.

Tae-Seong Lee, Toshihiko Kaku, Satoshi Takebayashi, Tomoko Uchino, Shinji Miyamoto, Tetsuo Hadama, Edward Perez-Reyes, Katsushige Ono

Department of Cardiovascular Science, Oita University School of Medicine, Oita, Japan.

Pharmacology 2006

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We compared detailed efficacy of efonidipine and nifedipine, dihydropyridine analogues, and mibefradil using recombinant T- and L-type Ca2+ channels expressed separately in mammalian cells. All these Ca2+ channel antagonists blocked T-type Ca2+ channel currents (I(Ca(T))) with distinct blocking manners: I(Ca(T)) was blocked mainly by a tonic manner by nifedipine, by a use-dependent manner by mibefradil, and by a combination of both manners by efonidipine. IC50s of these Ca2+ channel antagonists to I(Ca(T)) and L-type Ca2+ channel current (I(Ca(L))) were 1.2 micromol/l and 0.14 nmol/l for nifedipine; 0.87 and 1.4 micromol/l for mibefradil, and 0.35 micromol/l and 1.8 nmol/l for efonidipine, respectively. Efonidipine, a dihydropyridine analogue, showed high affinity to T-type Ca2+ channel. Copyright 2006 S. Karger AG, Basel.

Citation

Tae-Seong Lee, Toshihiko Kaku, Satoshi Takebayashi, Tomoko Uchino, Shinji Miyamoto, Tetsuo Hadama, Edward Perez-Reyes, Katsushige Ono. Actions of mibefradil, efonidipine and nifedipine block of recombinant T- and L-type Ca channels with distinct inhibitory mechanisms. Pharmacology. 2006;78(1):11-20