Role of store-operated calcium entry in imperatorin-induced vasodilatation of rat small mesenteric artery.
Store-operated Ca(2+) entry (SOCE) has recently been proposed to contribute to Ca(2+) influx in vascular smooth muscle cells (VSMCs). Imperatorin is known for its potent vasodilatory effects as a dietary furanocoumarin. The study was designed to examine the hypothesis that SOCE have a functional role in imperatorin-induced vasodilation. Small mesenteric resistance arteries and mesenteric VSMCs were obtained from rats. Isometric tensions of isolated artery rings were measured by a sensitive myograph system. Laser scanning confocal microscopy was used to determine the intracellular Ca(2+) concentration of fluo-3-loaded VSMCs. Imperatorin (1-100 μM) relaxed artery rings precontracted by phenylephrine in a concentration-dependent manner. In cultured mesenteric VSMCs, passive store depletion by thapsigargin and active store depletion by phenylephrine both induced Ca(2+) influx due to SOCE. Imperatorin didn't inhibit SOCE-mediated increases in cytosolic Ca(2+) levels evoked by the emptying of the stores. In isolated artery rings, imperatorin didn't inhibit SOCE-induced contractions due to store depletion. Our results exclude SOCE mechanism of vasodilatation by imperatorin. But imperatorin is partly similar with nifedipine in vasorelaxation effect.
Zhang
Yan
Y
School of Medicine, Xi'an Jiaotong University, Xi'an, PR China.
Wang
Qun Li
QL
Zhan
Ying Zhuan
YZ
Duan
Hai Jie
HJ
Cao
Yan Jun
YJ
He
Lang Chong
LC
D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects; D011564:Furocoumarins / Q000378:metabolism* / Q000494:pharmacology; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000378:metabolism* / Q000494:pharmacology; D014966:Xanthenes / Q000378:metabolism
D000814:Aniline Compounds; D015220:Calcium Channels; D011564:Furocoumarins; D014665:Vasodilator Agents; D014966:Xanthenes; C059715:Fluo-3; C031534:imperatorin; D002118:Calcium