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- Title
Quercetin enhances human α7 nicotinic acetylcholine receptor-mediated ion current through interactions with Ca binding sites.
- Authors
Lee, Byung-Hwan; Choi, Sun-Hye; Shin, Tae-Joon; Pyo, Mi; Hwang, Sung-Hee; Kim, Bo-Ra; Lee, Sang-Mok; Lee, Jun-Ho; Kim, Hyoung-Chun; Park, Hye-Young; Rhim, Hyewhon; Nah, Seung-Yeol
- Abstract
The flavonoid quercetin is a low molecular weight substance found in fruits and vegetables. Aside from its anti-oxidative effect, quercetin, like other flavonoids, has a wide range of neuropharmacological actions. The α7 nicotinic acetylcholine receptor (α7 nAChR) has a Ca-binding site, is highly permeable to the Ca ion, and plays important roles in Ca-related normal brain functions. Dysfunctions of α7 nAChR are associated with a variety of neurological disorders. In the present study, we investigated the effects of quercetin on the ACh-induced inward peak current ( I ) in Xenopus oocytes that heterologously express human α7 nAChR. I was measured with the two-electrode voltage clamp technique. In oocytes injected with α7 nAChR cRNA, the effects of the co-application of quercetin on I were concentration-dependent and reversible. The ED was 36.1 + 6.1 μM. Quercetin-mediated enhancement of I caused more potentiation when quercetin was pre-applied. The degree of I potentiation by quercetin pre-application was time-dependent and saturated after 1 min. Quercetin-mediated I enhancement was not affected by ACh concentration and was voltage-independent. However, quercetin-mediated I enhancement was dependent on extracellular Ca concentrations and was specific to the Ca ion, since the removal of extracellular Ca or the addition of Ba instead of Ca greatly diminished quercetin enhancement of IACh. The mutation of Glu195 to Gln195, in the Ca-binding site, almost completely diminished quercetin-mediated I enhancement. These results indicate that quercetin-mediated I enhancement human α7 nAChR heterologously expressed in Xenopus oocytes could be achieved through interactions with the Ca-binding site of the receptor.
- Publication
Molecules & Cells (Springer Nature), 2010, Vol 30, Issue 3, p245
- ISSN
1016-8478
- Publication type
Article
- DOI
10.1007/s10059-010-0117-9