Mibefradil
Names
Biological Activity
[Description]:
Mibefradil 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.
[Related Catalog]:
[Target]
IC50: 2.7 μM (T-type calcium channel), 18.6 μM (L-type calcium channel)[1]
[In Vitro]
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].
[In Vivo]
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 CaV3.2 expression in the spinal cord and DRG[4].
[Animal admin]
Mice[3] A total of 30 male C57BL/6J mice (age, 6-8 weeks) are randomized into three groups for the detection of three calcium channel receptor subunits α1G, α1H and α1I, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, a further 30 C57BL/6J male mice (age, 24-26 weeks) are allocated at random into three treatment groups: Saline, Mibefradil and benidipine. Each group is subjected to auditory brainstem recording (ABR) and distortion product otoacoustic emission (DPOAE) tests following treatment. Mibefradil and benidipine are dissolved in physiological saline solution. A preliminary experiment led to the selection of dosages of 30 mg/kg/day Mibefradil and 10 mg/kg/day Benidipine. The drugs are administered to the mice by gavage for four consecutive weeks. Rats[4] Male Sprague-Dawley rats (200-250 g) are used for right L5/6 SNL to induce neuropathic pain. Intrathecal infusion of saline or TCC blockers [Mibefradil (0.7 μg/h) or Ethosuximide (60 μg/h)] is started after surgery for 7 days. Fluorescent immunohistochemistry and Western blotting are used to determine the expression pattern and protein level of CaV3.2. Hematoxylin-eosin and toluidine blue staining are used to evaluate the neurotoxicity of tested agents.
[References]
[Related Small Molecules]
Chemical & Physical Properties
[ Density]:
1.18g/cm3
[ Boiling Point ]:
647.6ºC at 760mmHg
[ Molecular Formula ]:
C29H38FN3O3
[ Molecular Weight ]:
495.62900
[ Flash Point ]:
345.5ºC
[ Exact Mass ]:
495.29000
[ PSA ]:
67.45000
[ LogP ]:
5.27090
[ Vapour Pressure ]:
1.17E-16mmHg at 25°C
[ Index of Refraction ]:
1.585
[ Storage condition ]:
2-8℃