Enhanced Vasorelaxation of Banhabackchulchunma-Tang and Involved Mechanism

반하백출천마탕(半夏白朮天麻湯)의 조성에 따른 혈관이완활성과 기전

This study was designed to potentiate the vasodilation effect of Banhabackchulchunma-Tang(BCT) prescription by change of mixture. Six different BCT compositions were made according to mixture of herbs. The vascular relaxation effects of 6 different BCT compositions were examined on phenylephrine(PE)-precontracted rat thoracic aorta. The BCT-1 composition exerted significant relaxation on phenylephrine- or KCI- contracted rat thoracic aorta. Its elaxation was endothelium- independent in both PE- and KCl-induced contraction. Treatment of glibenclamide or tetraethylammonium(TEA) did not affect the relaxation of BCT-1. Vasorelaxation efficacy of BCT-1 was also not influenced by low (25mM) or high (50mM, 80mM) KCl-induced contraction. Furthermore, the contraction by increasing $Ca^{2+}$ concentrations (0.3-10.0mM) to a $Ca^{2+}$-free high K+ (60mM) was significantly reduced by pretreatment with BCT-1 In addition, the relaxant effects were not inhibited by pretreatment of rat aorta with L-NAME, MB, indomethacin and atropine. These results confirm that BCT-1 may exerts its vasodilation effect by endothelium-independent manner. According to the above results, we suggest that the relaxation effect of BCT-1 is endothelium-independent and is related with block of $Ca^{2+}$ influx via $Ca^{2+}$ channel.