Vasorelaxant effect and underlying mechanism of EtOAc extract from Chrysanthemum morifolium in rat thoracic aorta / 中国病理生理杂志

ABSTRACT

AIM: To investigate the vasorelaxant effect and mechanism of EtOAc extract from Chrysanthemum morifolium Ramat (CME). METHODS: The effects of CME on the contraction of rat thoracic a orta were examined. RESULTS: CME caused concentration-dependent relaxation of aorta rings precontricted with phenylephrine and K+. The effect in endothelium-intac t aorta was more effective than that in endothelium-deduced aorta. NG-nitro-L- arginine methylester, methylene blue and glibenclamide attenuated the effect of C ME significantly. However, indomethacin, propranolol, tetraethylammonium, BaCl 2, 4-aminopyridine and 5-hydroxydecanoate did not affect CME effect. The effect of SKF-525A combined with L-NAME had no obvious difference with that of L-NAME o n CME-induced relaxation. NOS activity in aorta was increased markedly by CME in vitro. CME did not reduced the contraction elicited by PE in Ca 2+-f ree medium, but reduced the contraction induced by PE in K+-free solution or C a 2+ free following input Ca 2+. CONCLUSION: CME induces both endothelium-dependent and independe nt relaxation. NO and cGMP are likely involved in the endothelium-dependent rela xation, inhibition of voltage-dependent or receptor-operate Ca 2+ channel a nd activation of ATP-sensitive K+ channel contribute in part to the endotheliu m-independent relaxation by CME.