Goshuyuto, a Traditional Japanese Medicine, and Aqueous Extracts of Evodiae Fructus Constrict Isolated Rat Aorta via Adrenergic and/or Serotonergic Receptors

Effects of goshuyuto, a traditional Japanese medicine, on vascular constriction were examined using isolated strips of rat aorta. Goshuyuto (1×10−5 to 1×10−3 g/ml) caused constriction of aorta strips in a dose-dependent manner. The vasoconstrictive effects of goshuyuto were significantly inhibited by pretreatment with prazosin, an adrenergic α1 receptor antagonist. The constrictive effects were partially inhibited by pretreatment with BRL15572, a 5-HT1D antagonist, and ketanserin, a 5-HT2A antagonist. However, the constrictive effects were not inhibited by pretreatment with SB216641, a 5-HT1B antagonist, or propranolol, an adrenergic β receptor antagonist. In addition, aqueous extracts of Evodiae Fructus, one of the constituent medicinal herbs of goshuyuto, caused constriction of aorta strips strongly, but aqueous extracts of Zizyphi Fructus, Ginseng Radix, and Zingiberis Rhizoma, the other constituents of goshuyuto, did not have much effect on the vascular response of rat aorta strips. Also, synephrine, which is one of the ingredients of Evodiae Fructus, constricted the rat aorta. These results suggest that goshuyuto constricts rat aorta strips and that the mechanisms involve the adrenergic and/or serotonergic receptors. Also, it may be suggested that Evodiae Fructus and synephrine play the important role in the vasoconstrictive effects of goshuyuto on rat aorta strips.