[The pharmacological studies on matrine and oxymatrine]

Matrine and oxymatrine, major components of Sophora flavescens, were confirmed to have a protective effect on restraint and water immersion stress ulcer in mice. Oxymatrine inhibits the formation of some experimental gastric ulcer, pylorus ligation ulcer and indomethacin ulcer, which are considered to relate to acid secretion. Oxymatrine decreases acid secretion in Shay's rats and inhibits gastric motility induced by restraint and water immersion stress when administered intraduodenally. These results suggest that the protective effect of oxymatrine on stress ulcer is possibly due to a decrease of acid secretion and inhibition of gastric motility. In spite of its weak inhibition of gastric acid secretion, intravenous injection of matrine is rather effective for stress ulcer. Matrine exhibits the inhibition of writhing induced by acetic acid, prolongation of sleeping time induced by pentobarbital, hypothermia and inhibition of locomotor activity induced by methamphetamine. Matrine (i.v.) also inhibits gastric motility induced by restraint and water immersion stress. On the other hand, the administration of matrine exhibits clear contraction on the preparation of the fundus strip of rats at high concentration. The contractile response of the fundus strip to matrine is not inhibited by treatment with tetrodotoxin, and is not modified with atropine, while pretreatment of the fundus strip with antihistamine abolished or reduced the contractile response. It can therefore be assumed that the direct action of matrine on the stomach smooth muscle possibly contributes to the mechanism of the matrine induced inhibition of the spontaneous gastric motility and rise in the tone of stomach, and may play an important role in the protection of the restraint and water immersion stress ulcer formetion.