title: Inhibitory effects of magnolol on voltage-gated Na+ and K+ channels of NG108-15 cells.
abstract: Magnolol, a polyphenolic compound isolated from Houpu, a Chinese herb from the bark of Magnolia officinalis, has been reported to have in vitro and in vivo neuroprotective effects. In spite of these reported beneficial effects, studies on the direct impact of magnolol on neuronal ion channels have been scarce. Whether magnolol affects voltage-gated Na(+) channels (VGSC) and voltage-gated K(+) (Kv) channels is unknown. Using the whole-cell voltage-clamp method, we studied the effects of magnolol on voltage-gated ion channels in neuronal NG108-15 cells. Magnolol inhibited VGSC channels with mild state-dependence (IC(50) of 15 and 30 μM, at holding potentials of -70 and -100 mV, respectively). No frequency-dependence was observed in magnolol block. Magnolol caused a left-shift of 18 mV in the steady-state inactivation curve but did not affect the voltage-dependence of activation. Magnolol inhibited Kv channels with an IC(50) of 21 μM, and it caused a 20-mV left-shift in the steady-state inactivation curve without affecting the voltage-dependence of activation. In conclusion, magnolol is an inhibitor of both VGSC and Kv channels and these inhibitory effects may in part contribute to some of the reported neuroprotective effects of magnolol.
authors.affiliation: Department of Physiology, China Medical University, Taichung 40402, Taiwan.
authors.forename: Chi-Li
authors.initials: CL
authors.lastname: Gong
authors.forename: Kar-Lok
authors.initials: KL
authors.lastname: Wong
authors.forename: Ka-Shun
authors.initials: KS
authors.lastname: Cheng
authors.forename: Chang-Shin
authors.initials: CS
authors.lastname: Kuo
authors.forename: Chia-Chia
authors.initials: CC
authors.lastname: Chao
authors.forename: Min-Fan
authors.initials: MF
authors.lastname: Tsai
authors.forename: Yuk-Man
authors.initials: YM
authors.lastname: Leung
mesh_terms: D001713:Biphenyl Compounds / Q000494:pharmacology*; D045744:Cell Line, Tumor; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects; D017705:Lignans / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D024642:Potassium Channels, Voltage-Gated / Q000037:antagonists & inhibitors / Q000378:metabolism*; D026941:Sodium Channel Blockers / Q000494:pharmacology*; D015222:Sodium Channels / Q000378:metabolism*
chemical_list: D001713:Biphenyl Compounds; D017705:Lignans; D018696:Neuroprotective Agents; D026902:Potassium Channel Blockers; D024642:Potassium Channels, Voltage-Gated; D026941:Sodium Channel Blockers; D015222:Sodium Channels; C005498:magnolol