摘要：Quercetin is a low molecular weight flavonoid found in dietary fruits and vegetables. Quercetin, like other flavonoids, has demonstrated neuroprotective effects in vitro and in vivo . However, relatively little is known about how quercetin achieves its neuroprotective abilities. The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor is one of several excitatory receptors, which play an important role in postsynaptic neurotransmission. Over-stimulation of ionotropic glutamate receptor including AMPA receptors is closely associated with excitatory neurotoxicities. In the present study, we investigated the effects of quercetin on the glutamate-induced inward current ( I Glu) in Xenopus oocytes that heterologously express human AMPA receptor and stargazin, an auxiliary subunit of AMPA receptor. I Glu was measured using the two-electrode voltage clamp technique. In oocytes injected with cRNAs coding AMPA receptor (GluR1) and stargazin, quercetin inhibited I Glu in a reversible and concentration-dependent manner. The IC50 was 84.9±15.0 μ M . Quercetin action on I Glu was attenuated by increasing glutamate concentration, and was membrane holding potential-dependent. These results show a possibility that quercetin interacts with AMPA receptor, which was heterologously expressed in Xenopus oocytes and that quercetin action on I Glu of AMPA receptor could be one of contributions of quercetin-mediated neuroprotections.
