Mibefradil  (Synonyms: Ro 40-5967)

Mibefradil (Ro 40-5967) is a calcium channel blocker with moderate selectivity for T-type Ca²⁺ channels displaying IC₅₀s of 2.7 μM and 18.6 μM for T-type and L-type currents, respectively^[1].

IC50: 2.7 μM (T-type calcium channel), 18.6 μM (L-type calcium channel)^[1]

Mibefradil inhibits reversibly the T- and L-type currents with IC₅₀ values of 2.7 and 18.6 μM, respectively. The inhibition of the L-type current is voltage-dependent, whereas that of the T-type current is not. Ro 40-5967 blocks T-type current already at a holding potential of -100 mV^[1] At a higher concentration (20 µM), Mibefradil reduces the amplitude of excitatory junction potentials (by 37±10 %), slows the rate of repolarisation (by 44±16 %) and causes a significant membrane potential depolarisation (from −83±1 mV to −71±5 mV). At a higher Mibefradil concentration (20 µM) there is significant membrane potential depolarisation and a slowing of repolarisation. These actions of Mibefradil are consistent with K⁺ channel inhibition, which has been shown to occur in human myoblasts and other cells^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

The hearing thresholds of the 24-26 week old C57BL/6J mice differed following the 4-week treatment period. The hearing threshold at 24 kHz is significantly decreased in the Mibefradil-treated and benidipine-treated groups compared with the saline-treated group (P<0.05)^[3]. Compared with the saline-treated group, rats receiving Mibefradil or Ethosuximide show significant lower Ca_V3.2 expression in the spinal cord and DRG^[4].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

495.63

C₂₉H₃₈FN₃O₃

116644-53-2

O=C(O[[email protected]@]1(CCN(CCCC2=NC3=CC=CC=C3N2)C)[[email protected]@H](C(C)C)C4=C(C=C(F)C=C4)CC1)COC

Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Mehrke G, et al. The Ca(++)-channel blocker Ro 40-5967 blocks differently T-type and L-type Ca++ channels. J Pharmacol Exp Ther. 1994 Dec;271(3):1483-8.  [Content Brief]

  [2]. Brain KL, et al. The sources and sequestration of Ca(2+) contributing to neuroeffector Ca(2+) transients in the mouse vas deferens. J Physiol. 2003 Dec 1;553(Pt 2):627-35.  [Content Brief]

  [3]. Yu YF, et al. Protection of the cochlear hair cells in adult C57BL/6J mice by T-type calcium channel blockers. Exp Ther Med. 2016 Mar;11(3):1039-1044.  [Content Brief]

  [4]. Shiue SJ, et al. Chronic intrathecal infusion of T-type calcium channel blockers attenuates CaV3.2 upregulation in nerve-ligated rats. Acta Anaesthesiol Taiwan. 2016 Oct 17. pii: S1875-4597(16)30071-6.  [Content Brief]