Weisbrodt N W, Sussman S S, Stewart J J, Burks T F
J Pharmacol Exp Ther. 1980 Aug;214(2):333-8.
A study was designed to determine the effects of morphine sulfate on small intestinal propulsion and small intestinal myoelectric activity in conscious rats. Adult male rats were divided into two groups. Each member of one group was implanted with an indwelling catheter in the proximal duodenum. Each member of the other group was implanted with electrodes on the serosal surface of the proximal small bowel. Intestinal transit was determined by administering a bolus of radioactive chromium (Na2 51CrO4, 0.5 muCi) in 0.2 ml of saline via the catheter and following its progression through the small intestine. In fasted rats, morphine sulfate administered s.c. inhibited intestinal transit of 51Cr in a dose-dependent manner between 1 and 25 mg/kg. Intestinal motility was determined by monitoring intestinal myoelectric activity both before and after administration of morphine sulfate. In fasted rats, s.c. administration of morphine caused an inhibition of spike potential activity. The inhibition was dose-dependent between dosages of 1 and 25 kg/kg. We conclude that morphine sulfate causes a dose-dependent inhibition of intestinal transit in fasted rats and that this inhibition is correlated with a dose-dependent inhibition of spike potentials of the intestinal smooth muscle cells.
一项研究旨在确定硫酸吗啡对清醒大鼠小肠推进运动和小肠肌电活动的影响。成年雄性大鼠被分为两组。一组的每只大鼠在十二指肠近端植入一根留置导管。另一组的每只大鼠在小肠近端浆膜表面植入电极。通过经导管给予0.2 ml含放射性铬（Na2 51CrO4，0.5微居里）的生理盐水推注，并跟踪其在小肠中的推进过程来测定肠道转运。在禁食大鼠中，皮下注射硫酸吗啡在1至25 mg/kg剂量范围内以剂量依赖性方式抑制51Cr的肠道转运。通过监测硫酸吗啡给药前后的肠道肌电活动来测定肠道运动。在禁食大鼠中，皮下注射吗啡会抑制锋电位活动。在1至25 kg/kg剂量之间，这种抑制呈剂量依赖性。我们得出结论，硫酸吗啡在禁食大鼠中引起剂量依赖性的肠道转运抑制，并且这种抑制与肠道平滑肌细胞锋电位的剂量依赖性抑制相关。
