The Mechanism Of The Effect Of Progesterone On The Function Of Rabbit Duodenum

Progesterone which has a wide hysiological functions is a very important hormone to regulate the reproductive function of female animal.Progesterone not only has a certain regulative action on female reproductive organs or tissues such as uterus、ovarian、breast and so on,but also has the activity of non-reproductive function such as regulate the activitives of central nervous system(brain, hypothalamus and so on), peripheral ganglion、stomach,intestines, cholecyst, cardiovascular system, bone metabolism, and so on. Clinical studies have found, the gastrointestinal tract of pregnant women exist “The smooth muscle relaxation syndrome”, so the effect of progesterone on gastrointestinal tract has attracted more and more attention in clinical research.The physiological action of progesterone in the body has tissue specificity, progesterone receptor mediate the function of progesterone.Detecting the existence of progesterone receptor in the duodenum to provide morpholoogic evidence of the effects of progesterone on the activity of duodenum.Acetylcholine receptor M3 and adrenergic receptor β3 is the typical receptor of neurotransmitter in the gastrointestinal tract,using double-label immunofluorescence to research the coexistence of PR and M3 m AchR、β3AR in the small intestine is the foundation to research the possible mechanism of action of progesterone and combined effects with neurotransmitter.MMC is the major indexes to assess the gastrointestinal smooth muscle activity, MMC occurring in the antrum or duodenal sinus of fasting、awake animals and human is a cyclic、repeated motor pattern and can migrate along the gastrointestinal tract.In order to research the effect of progesterone on the duodenal smooth muscle, we use a pair of silver electrodes from perpendicular to the longitudinal muscle of duodenal was stabed to the muscular subserosal,then the electrode was connected to the BL-420 F biological functional experimental system to record the MMC of rabbit duodenal smooth muscle and compared the amplitude and frequence of the slow wave, and the change of the cycle of MMC of duodenal smooth muscle of different rabbits which treated with different concentration of progesterone. The test results are as follows:1. Used immunohistochemical SP staining to detect the progesterone receptors in the rabbit duodenum, the results showed that, PR uniformly strong immunostaining exit in the cylindrical cells of duodenal glands located in the submucosa and intestinal epithelial cell.Moderate immunoreactivity products distribute in the smooth muscle cells of the muscular layer and muscularis mucosa.2. Double-label immunofluorescence staining method was used to research the coexistence of the PR and M3 mAchR in the duodenum of healthy adult rabbit.The two receptors mainly coexist in the cylindrical cells of duodenal glands located in the submucosa and intestinal epithelial cells. In the smooth muscle cells of the muscular layer and muscularis mucosa also coexist the two receptor.PR and β3AR mainly coexit in the cells of enteraden located in the lamina propria and intestinal epithelial cells.In the jejunum and ileum, the PR and M3 mAchR mainly coexit in the cells of enteraden located in the lamina propria, intestinal epithelial cells,the smooth muscle cells of the muscular layer and muscularis mucosa. PR and β3AR mainly coexist in the enteraden located in the lamina propria and intestinal epithelial cells.3. The result of the physiological experiments are as follows:The characteristic of the MMC of duodenal smooth muscle of the normal rabbit is an obvious positive and negative two-way wave, the shape of MMC of the castration rabbits are consistent with the normal rabbits. Compared to the slow wave of the normal rabbits, the amplitude of the slow wave of the castration rabbits was decreased(P<0.01), the time of the phaseⅢ was shortened(P<0.05). Compared to the MMC of the castration rabbits, The time of phaseⅢ of 5mg/kg progesterone treatment group was shorter(P>0.05), the amplitude of the slow wave was low(P<0.05), When treated with 10mg/kg progesterone, the amplitude of the slow wave was significantly increased(P<0.01), and the time of phaseⅢ was significantly prolonged(P>0.01), the effect of 15mg/kg and 20mg/kg progesterone is reduce the amplitude of the slow wave(P<0.01) and the time of phaseⅢ((P<0.05). The spike activity of the duodenal smooth muscle was weakened.The antagonist of progesterone receptor has the antagonism to progesterone. So, progesterone has the dose-dependent on the effect of the duodenal smooth muscle, progesterone show opposite effect with different concentration.