期刊
VASCULAR PHARMACOLOGY
卷 44, 期 5, 页码 338-344出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.vph.2006.01.009
关键词
labdane-302; Xylopia langsdorffianna; superior mesenteric artery; vasorelaxation; whole-cell patch clamp; calcium currents
The cardiovascular effects induced by labdane-302, a diterpene isolated from the stems of Xylopia langsdorffianna St. Hill and Tull, were evaluated in male Wistar rats. In normotensive, conscious animals, labdane-302 produced dose-dependent hypotension and tachycardia. These effects were significantly attenuated after pre-treatment with L-NAME (20mg/kg, i.v.). In isolated mesenteric artery rings, labdane-302 (10(-4)-10(-4) M) elicited concentration-dependent relaxation of phenylephrine-induced contractions (IC50 = 5.4 +/- 1.4 mu M). Endothelium removal, and pretreatment with L-NAME (100 mu M) or indomethacin (10 mu M) caused significant reductions in sensitivity. Labdane-302 also caused concentration-dependent relaxation in arterial rings pre-contracted with high extracellular KCI (80mM). In Ca2+-free depolarized preparations, labdane-302 inhibited contractions produced by cumulative increases in extracellular Ca2+ concentration. In GH3 cells, labdane-302 (100 mu M) inhibited whole-cell L-type Ca2+ currents by similar to 50%. These results demonstrate that labdane-302 causes hypotension through peripheral vasodilation, mediated in part by NO and PGI(2) and by blockade of Ca2+ entry through L-type Ca2+ channels. (c) 2006 Elsevier Inc. All rights reserved.
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