title: Resveratrol Inhibits GABAC ρ Receptor-Mediated Ion Currents Expressed in Xenopus Oocytes.
abstract: Resveratrol is a phytoalexin found in grapes, red wine, and berries. Resveratrol has been known to have many beneficial health effects, such as anti-cancer, neuroprotective, anti-inflammatory, and life-prolonging effects. However, relatively little is known about the effects of resveratrol on the regulation of ligand-gated ion channels. We have previously reported that resveratrol regulates subsets of homomeric ligand-gated ion channels such as those of 5-HT3A receptors. The γ-aminobutyric acidC (GABAC) receptor is mainly expressed in retinal bipolar cells and plays an important role in visual processing. In the present study, we examined the effects of resveratrol on the channel activity of homomeric GABAC receptor expressed in Xenopus oocytes injected with cRNA encoding human GABAC ρ subunits. Our data show that the application of GABA elicits an inward peak current (IGABA ) in oocytes that express the GABAC receptor. Resveratrol treatment had no effect on oocytes injected with H2O or with GABAC receptor cRNA. Co-treatment with resveratrol and GABA inhibited IGABA in oocytes with GABAC receptors. The inhibition of IGABA by resveratrol was in a reversible and concentration-dependent manner. The IC50 of resveratrol was 28.9±2.8 µM in oocytes expressing GABAC receptor. The inhibition of IGABA by resveratrol was in voltage-independent and non-competitive manner. These results indicate that resveratrol might regulate GABAC receptor expression and that this regulation might be one of the pharmacological actions of resveratrol on the nervous system.
authors.affiliation: Department of Physiology, College of Veterinary Medicine and Bio-Molecular Informatics Center, Konkuk University, Seoul 143-701, Korea.
authors.forename: Byung-Hwan
authors.initials: BH
authors.lastname: Lee
authors.forename: Sun-Hye
authors.initials: SH
authors.lastname: Choi
authors.forename: Sung-Hee
authors.initials: SH
authors.lastname: Hwang
authors.forename: Hyeon-Joong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Joon-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Seung-Yeol
authors.initials: SY
authors.lastname: Nah
keywords: GABAC receptor; Ligand-gated ion channel; Resveratrol; Xenopus oocyte