کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2574752 1129711 2006 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Vasorelaxant effect of euxanthone in the rat thoracic aorta
موضوعات مرتبط
علوم پزشکی و سلامت پزشکی و دندانپزشکی کاردیولوژی و پزشکی قلب و عروق
پیش نمایش صفحه اول مقاله
Vasorelaxant effect of euxanthone in the rat thoracic aorta
چکیده انگلیسی

This study was undertaken to investigate the effect of euxanthone on isolated rat thoracic aorta. Euxanthone concentration-dependently relaxed high K+-induced sustained contractions with IC50 values of 32.28 ± 1.73 μM and this inhibition was antagonized by increasing the Ca2+ concentration in the medium. These results indicated that euxanthone may have calcium antagonistic property. Euxanthone also relaxed norepinephrine (NE)-induced sustained contractions with IC50 values of 32.50 ± 2.15 μM and this relaxant effect was unaffected by the removal of endothelium or by the presence of propranolol, indomethacin, glibenclamide or Nω-nitro-l-arginine. Moreover, euxanthone inhibited both the phasic and tonic contractions induced by NE in a concentration-dependent manner and showed more potent inhibition on phasic contraction (P < 0.01). Pre-treatment with euxanthone inhibited vascular contraction induced by phorbol 12, 13-dibutyrate (PDBu), a protein kinase C (PKC) agonist, in either the presence or absence of Ca2+ in the solution with IC50 values of 20.15 ± 1.56 and 18.30 ± 1.62 μM, respectively. However, when the tissues were treated with euxanthone after the PDBu-induced contraction had reached a steady state, the tension was not affected by euxanthone. This study also showed that the inhibitory effect of pre-treatment of euxanthone was more potent than the post-treatment after the tension had reached a steady state. These results suggested that the vasorelaxation of euxanthone may be through multiple pathways involved PKC-mediated signal pathway and calcium-independent pathway besides the direct inhibition of calcium influx and its vasorelaxant effect is more active on calcium-independent pathway and more sensitive to the initial stage of contraction.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Vascular Pharmacology - Volume 45, Issue 2, August 2006, Pages 96–101
نویسندگان
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