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

Mibefradil dihydrochloride 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 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.

西域 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 differ 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). Compared with the saline-treated group, rats receiving Mibefradil or NSC 64013 show significant lower Ca_V3.2 expression in the spinal cord and DRG^[4].

西域 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 differ 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). Compared with the saline-treated group, rats receiving Mibefradil or NSC 64013 show significant lower Ca_V3.2 expression in the spinal cord and DRG^[4].

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

• . 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]

  . 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]

  . 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]