Differential Effects of Quercetin and Quercetin Glycosides on Human alpha 7 Nicotinic Acetylcholine Receptor-Mediated Ion Currents

Title
Differential Effects of Quercetin and Quercetin Glycosides on Human alpha 7 Nicotinic Acetylcholine Receptor-Mediated Ion Currents
Authors
임혜원이병환최선혜김현중정석원황성희표미경김형근김호경이상목나승열
Issue Date
2016-07
Publisher
Biomolecules & Therapeutics
Citation
VOL 24, NO 4-417
Abstract
Quercetin is a flavonoid usually found in fruits and vegetables. Aside from its antioxidative effects, quercetin, like other flavonoids, has a various neuropharmacological actions. Quercetin-3-O-rhamnoside (Rham1), quercetin-3-O-rutinoside (Rutin), and quercetin-3-(2(G)-rhamnosylrutinoside (Rham2) are mono-, di-, and tri-glycosylated forms of quercetin, respectively. In a previous study, we showed that quercetin can enhance alpha 7 nicotinic acetylcholine receptor (alpha 7 nAChR)-mediated ion currents. However, the role of the carbohydrates attached to quercetin in the regulation of alpha 7 nAChR channel activity has not been determined. In the present study, we investigated the effects of quercetin glycosides on the acetylcholine induced peak inward current (I-ACh) in Xenopus oocytes expressing the alpha 7 nAChR. I-ACh was measured with a two-electrode voltage clamp technique. In oocytes injected with alpha 7 nAChR copy RNA, quercetin enhanced I-ACh, whereas quercetin glycosides inhibited I-ACh. Quercetin glycosides mediated an inhibition of I-ACh, which increased when they were pre-applied and the inhibitory effects were concentration dependent. The order of I-ACh inhibition by quercetin glycosides was Rutin >= Rham1>Rham2. Quercetin glycosides -mediated lath enhancement was not affected by ACh concentration and appeared voltage-independent. Furthermore, quercetin-mediated I-ACh, inhibition can be attenuated when quercetin is co-applied with Rham1 and Rutin, indicating that quercetin glycosides could interfere with quercetin-mediated alpha 7 nAChR regulation and that the number of carbohydrates in the quercetin glycoside plays a key role in the interruption of quercetin action. These results show that quercetin and quercetin glycosides regulate the alpha 7 nAChR in a differential manner.
URI
http://pubs.kist.re.kr/handle/123456789/64696
ISSN
1976-9148
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KIST Publication > Article
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