title: Effects of ginsenoside Rg3 on α9α10 nicotinic acetylcholine receptor-mediated ion currents.
abstract: Ginsenosides is a low molecular weight substance found in ginseng as one of the active ingredients. Ginsenosides, like other herbal medicines, has a wide range of neuropharmacological actions including neuroprotective effects. The α9α10 nicotinic acetylcholine receptor is one of numerous nicotinic acetylcholine receptors that exists as a heteropentameric form in auditory hair cells of the cochlea. In this study, we report the effects of ginsenosides on rat α9α10 nicotinic acetylcholine receptor-mediated ion currents using the two-electrode voltage clamp technique. Treatment with acetylcholine evoked inward currents (IACh) in oocytes heterologously expressing the α9α10 nicotinic acetylcholine receptor. Ginsenosides blocked IACh in order of potency of Rg3> Rb2> CK>Re = Rg2> Rf>Rc> Rb1> Rg1 with reversible manners, and the blocking effect of Rg3 on IACh was same after pre-application than co-application of Rg3. The half maximal inhibitory concentration (IC50) of Rg3 was 39.6 ± 4.9 µm. Rg3-induced IACh inhibition was not affected by acetylcholine concentration and was independent of membrane holding potential. Although the inhibitory effect of Rg3 on IACh was abolished in oocytes expressing α9 subunit alone, indicating that the presence of α10 subunit might be required for Rg3-induced regulations of α9α10 nicotinic acetylcholine receptor channel activity. These results indicate that α10 subunit of α9α10 nicotinic acetylcholine receptor might play an important role in Rg3-induced regulation of the α9α10 nicotinic acetylcholine receptor.
authors: Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, Seoul 143–701, Korea.
authors: Byung-Hwan
authors: BH
authors: Lee
authors: Sun-Hye
authors: SH
authors: Choi
authors: Sung-Hee
authors: SH
authors: Hwang
authors: Hyeon-Joong
authors: HJ
authors: Kim
authors: Sang-Mok
authors: SM
authors: Lee
authors: Hyoung-Chun
authors: HC
authors: Kim
authors: Hyewhon
authors: H
authors: Rhim
authors: Seung-Yeol
authors: SY
authors: Nah
mesh_terms: D000818:Animals; D005260:Female; D036145:Ginsenosides / Q000494:pharmacology*; D066298:In Vitro Techniques; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D021122:Protein Subunits / Q000502:physiology*; D051381:Rats; D011978:Receptors, Nicotinic / Q000502:physiology*; D014982:Xenopus laevis
chemical_list: C498541:Chrna9 protein, rat; D036145:Ginsenosides; D021122:Protein Subunits; D011978:Receptors, Nicotinic; C097367:ginsenoside Rg3