Chinese medicinal herbs Muh-Shiang Bin-Lang-Wan increases the motility of sphincter of Oddi in anesthetized rabbits through activation of M1 muscarinic receptors

Abstract

The sphincter of Oddi (SO) plays an important role in regulating the bile flow into the duodenum. This study was designed to investigate the effect of Chinese Medicinal Herbs Muh-Shiang-Bin-Lang-Wan (MSBLW) and their mechanism of action on regulating the motility of SO in rabbits. The activity of SO in anesthetized rabbits was measured by using a continuously perfused open-tip manometric method. The rabbits were administered with different doses of MSBLW through naso-gastric tubes. The SO motility before and after the administration of MSBLW were recorded, and analyzed with a computer equipped with an off line analysis software. The results showed that the SO activity, in terms of tonic pressure and phasic contraction pressure, were significantly changed. A significant lower tonic pressure and a higher phasic contraction pressure were noticed 40–60 min after administration of MSBLW with a peak response at 0.5–1.0 gm range. The responses were blocked by pretreatment of muscarinic receptors (M1) antagonist, pirenzepine (10 mg/kg, orally). We conclude that MSBLW is effective in increasing the SO motility in rabbits through activation of M1 muscarinic receptors. However, potential application of MSBLW in the treatment of human biliary disorders needs further evaluation.