期刊
JOURNAL OF MOLECULAR AND CELLULAR CARDIOLOGY
卷 45, 期 3, 页码 437-445出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.yjmcc.2008.06.005
关键词
CNGA2 channels; epinephrine; isoprenaline; endothelial cells; Ca2+
资金
- Hong Kong Research Grant Council [Hong Kong Research Grant Council]
- Focused Investment Scheme of Chinese University of Hong Kong
- Li Ka Shing Institute of Health Sciences
Epinephrine, through its action on beta-adrenoceptors, may induce endothelium-dependent vascular dilation, and this action is partly mediated by a cytosolic Ca2+ ([Ca2+](i)) change in endothelial cells. In the present study, we explored the molecular identity of the channels that mediate epinephrine-induced endothelial Ca2+ influx and subsequent vascular relaxation. Patch clamp recorded an epinephrine- and cAMP-activated cation current in the primary cultured bovine aortic endothelial cells (BAECs) and H5V endothelial cells. L-cis-diltiazem and LY-83583, two selective inhibitors for cyclic nucleotide-gated channels, diminished this cation current. Furthermore, this cation current was greatly reduced by a CNGA2-specific siRNA in H5V cells. With the use of fluorescent Ca2+ dye, it was found that epinephrine and isoprenaline, a beta-adrenoceptor agonist, induced endothelial Ca2+ influx in the presence of bradykinin. This Ca2+ influx was inhibited by L-cis-diltiazem and LY-83583, and by a beta(2)-adrenoceptor antagonist ICI-118551. CNGA2-specific siRNA also diminished this Ca2+ influx in H5V cells. Furthermore, L-cis-diltiazem and LY-83583 inhibited the endothelial Ca2+ influx in isolated mouse aortic strips. L-cis-diltiazem also markedly reduced the endothelium-dependent vascular dilation to isoprenaline in isolated mouse aortic segments. In summary, CNG channels, CNGA2 in particular, mediate beta-adrenoceptor agonist-induced endothelial Ca2+ influx and subsequent vascular dilation. (C) 2008 Elsevier Inc. All rights reserved.
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