苦马豆总黄酮甙的降压作用及其机理

麻醉动物、清醒动物以及自发性高血压大鼠,iv苦马豆总黄酮甙后,均有显著的降压作用,起效快,持续时间短。降压机理与交感神经节阻断作用和直接扩张血管作用有关。血流动力学实验表明,苦马豆总黄酮甙对心肌收缩力和心率均无明显影响。由于外周扩血管作用而使总外周阻力明显降低。

Hypotensive effect and its mechanism of action of total flavonoidal glycosides of Swainsona salsula (Pall.) Taub.

Total flavonoidal glyco-sides (SSTFG) was extracted from Swainsona salsula (Pall.) Taub. Thehypotensive effect and its mechanism of action of SSTFG were investigated. The acute iv LD50 in mice is 186 (180- 191) mg/kg. Intravenous administration of SSTFG resulted in rapid and marked reduction in blood pressure in anesthetized animals (dog, cat and rat) and conscious rabbits as well. The lowering of blood pressure in the spontaneous hypertensive rats was 20±SD 10%(SSTFG5mg/kg) and 36±13% (10 mg/kg SSTFG), lasting for 15.4±SD 4.8 min and 23.0±7.4 min,respectively. Tachyphylaxis did not occur after repeated administration of SSTFG.SSTFG when administered via close artery into the superior cervical ganglion, abolished the contractile response of the nictitating membrane to stimulation of the preganglionic sympathetic fibers, the hypotensive effect of SSTFG was not attenuated by atro-pine,propranolol and diphenhydramine. The vasopressor effect of norepineph-rine did not diminished after administration of SSTFG. The perfusion flow in rabbit isolated ears was obviously increased by SSTFG. The effect on blood pressure of SSTFG injected via intravertebral artery was not significantly greater than that of intravenous SSTFG. The data derived from the hemodynamic experiments suggest that SSTFG is devoid of any inotropic and chronotropic effects on heart.It is proposed that SSTFG produces hypotensive effect via sympathetic ganglionic blockade and direct vasodi-lation.