Objective The purpose of the study was to observe the effect of
glycyrrhiza on
migrating myoelectric complex(MMC) in
small intestine in rats and to investigate the mechanism through which the effect occours.Methods Twenty adult SD rats were randomly divided into bethanoechol group and
glycyrrhiza group.MMC in small intestine in rats was measured before and after drug administration.Another 20 rats were randomly divided into normal control group and glycyrrhiza group.The content of 5 hydroxyptamine(5 HT) in enterochromaffin cell(EC) and enteric nervous system(ENS) was measured by immunohistochemical method in the two groups and the immunoreactivity in EC and ENS was determined quantatatively by microspectrophotometry.Results Glycyrrhiza inhibited and guarded against the contration of duodenum and jejunum induced by bethanechol.The content of 5 HT in EC and ENS in glycyrrhiza group was significantly lower than that of normal control group( P <0.05).The inhibition of MMC in small intestine in the rat was caused by the glycyrrhiza which inhibits the 5 HT secretion by phenochromocytes and the level of 5 HT in ENS.Conclusion One of the mechanisms of glycyrrhiza inhibiting MMC in duodenum and jejunum in the rats may be involved in postsynaptic inhibition induced by M receptor.The another mechanism of glycyrrhiza inhibition MMC in small intestine was that the secretion of 5 HT in EC and the content of 5 HT in ENS were decreased by glycyrrhiza .Thus the inhibition of the MMC in small intestine occurs.