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题名:Quercetin induces insulin secretion by direct activation of L-type calcium channels in pancreatic beta cells.
作者:BARDY G; VIRSOLVY A; QUIGNARD JF; RAVIER MA; BERTRAND G; DALLE S; CROS G; MAGOUS R; RICHARD S; OIRY C;
来源:Br J Pharmacol. 2013 Jul;169(5):1102-13. doi: 10.1111/bph.12194. [ IF= 0.00 ] ]
URL :10.1111/bph.12194
日期:20130830
摘要:BACKGROUND AND PURPOSE: Quercetin is a natural polyphenolic flavonoid that
displays anti-diabetic properties in vivo. Its mechanism of action on
insulin-secreting beta cells is poorly documented. In this work, we have analysed
the effects of quercetin both on insulin secretion and on the intracellular
calcium concentration ([Ca(2+)]i) in beta cells, in the absence of any
co-stimulating factor. EXPERIMENTAL APPROACH: Experiments were performed on both
INS-1 cell line and rat isolated pancreatic islets. Insulin release was
quantified by the homogeneous time-resolved fluorescence method. Variations in
[Ca(2+)]i were measured using the ratiometric fluorescent Ca(2+) indicator
Fura-2. Ca(2+) channel currents were recorded with the whole-cell patch-clamp
technique. KEY RESULTS: Quercetin concentration-dependently increased insulin
secretion and elevated [Ca(2+)]i. These effects were not modified by the SERCA
inhibitor thapsigargin (1 mumol.L(-1)), but were nearly abolished by the L-type
Ca(2+) channel antagonist nifedipine (1 mumol.L(-1)). Similar to the L-type
Ca(2+) channel agonist Bay K 8644, quercetin enhanced the L-type Ca(2+) current
by shifting its voltage-dependent activation towards negative potentials, leading
to the increase in [Ca(2+)]i and insulin secretion. The effects of quercetin were
not inhibited in the presence of a maximally active concentration of Bay K 8644
(1 mumol.L(-1)), with the two drugs having cumulative effects on [Ca(2+)]i.
CONCLUSIONS AND IMPLICATIONS: Taken together, our results show that quercetin
stimulates insulin secretion by increasing Ca(2+) influx through an interaction
with L-type Ca(2+) channels at a site different from that of Bay K 8644. These
data contribute to a better understanding of quercetin's mechanism of action on
insulin secretion.

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