|
KMID : 0811720090130050361
|
|
Korean Journal of Physiology & Pharmacology
2009 Volume.13 No. 5 p.361 ~ p.365
|
|
|
Possible Involvement of Ca2＋ Activated K＋ Channels, SK Channel, in the Quercetin-Induced Vasodilatation
|
|
Nishida Seiichiro
Satoh Hiroyasu
|
|
|
Abstract
|
|
|
|
Effects of quercetin, a kind of flavonoids, on the vasodilating actions were investigated. Among the mechanisms for quercetin-induced vasodilatation in rat aorta, the involvement with the Ca2＋ activated K＋ (KCa) channel was examined. Pretreatment with NE (5?M) or KCl (60 mM) was carried out and then, the modulation by quercetin of the constriction was examined using rat aorta ring strips (3 mm) at 36.5oC. Quercetin (0.1 to 100?M) relaxed the NE-induced vasoconstrictions in a concentration- dependent manner. NO synthesis (NOS) inhibitor, NG-monomethyl-L-arginine acetate (L-NMMA), at 100?M reduced the quercetin (100?M)-induced vasodilatation from 97.8±3.7% (n=10) to 78.0±11.6 % (n=5, p＜0.05). Another NOS inhibitor, L-NG-nitro arginine methyl ester (L-NAME), at 100?M also had the similar effect. In the presence of both 100?M L-NMMA and 10?M indomethacin, the quercetin-induced vasodilatation was further attenuated by 100?M tetraethylammonium (TEA, a KCa channel inhibitor). Also TEA decreased the quercetin-induced vasodilatation in endothelium-denuded rat aorta. Used other KCa channel inhibitors, the quercetin-induced vasodilatation was attenuated by 0.3?M apamin (a SK channel inhibitor), but not by 30 nM charybdotoxin (a BK and IK channel inhibitor). Quercetin caused a concentration-dependent vasodilatation, due to the endothelium- dependent and -independent actions. Also quercetin contributes to the vasodilatation selectively with SK channel on smooth muscle.
|
|
|
KEYWORD
|
|
|
Quercetin, Vasodilatation, KCa channels, PK-C, Endothelium
|
|
|
FullTexts / Linksout information
|
|
 
|
|
|
Listed journal information
|
|
  
|
|