NO合酶抑制剂在多巴胺抑制小鼠胃肠推进运动中的作用

目的 研究一氧化氮（ＮＯ）合酶抑制剂Ｌ－ＮＧ－硝基粗氨酸甲酯（Ｌ－ＮＡＭＥ）在多巴胺对小鼠胃肠运动影响中的作用。方法 将３２只小鼠随机分为３组；姐，静脉注生理盐水：Ａ组静脉注射多巴胺；Ｂ组静脉分别注射不同剂量的Ｌ－ＮＡＭＥ，１０ｍｉｎ后分别静脉注射多巴胺。采用含１２％活性炭和４％黄芪胶的炭末胶液灌胃，计算２０ｍｉｎ炭末胶液在小肠内推进距离占小肠全长的百分比，以此作为小肠推进速度的指标，同时测定灌胃

The role of NO biosynthesis inhibitor in dopamine-induced inhibition of mice gastric intestinal motility

Objective To study the role of the NO-biosynthesis inhibitor N-nitro-L-arginine methyl ester (L-NAME) in dopamine(DA)-induced gastrointestinal propulsion of mice.?Methods 32 mice were divided randomly into 3 groups: control group ( n =6) received normal saline intravenously; group A ( n =7) received dopamine intravenously; group B ( n =19) were pretreated with different dosage of L-NAME followed by intravenous dopamine 10 min later, respectively. A mixture of activated charcoal (12%) and gum tragacanth(4%) was perfused into the stomach of mouse. The percentage length of in small intestinal propulsion within 20 minutes was taken to express the intestinal propulsion speed and gastric emptying was assessed by measuring remained volume in the stomach.?Results DA significantly reduced the speed of intestinal propulsion and increased intragastric remained volume compared with those of control ( P <0.01, P <0.05);That DA inhibited The speed of small intestinal propulsion and gastric emptying was reversed by intravenous inhibitor of NO synthesis (L-NAME 3 mg/ kg).Pretreated by intravenous inhibitor of NO synthesis (L-NAME 6 mg/kg or 12 mg/kg), ?the speed of intestinal propulsion reduced by 3.8% and 18.8%, ? intragastric remained volume increased by 28.8% and 45.6% ( P <0.05), respectively.? Conclusion That DA-inhibited small intestinal propulsion may contribute to its delayed gastric emptying. NO is responsible for the DA-mediated small intestinal motility and gastric emptying.