Konturek S J, Thor P, Król R, Dembiński A, Schally A V
Am J Physiol. 1980 Apr;238(4):G384-9. doi: 10.1152/ajpgi.1980.238.4.G384.
Enkephalins, naturally occurring peptides with powerful opiatelike effects, have recently been detected throughout the tissues of the alimentary tract, but their role is unknown. This study was designed to compare the effects of methionine-enkephalin (met-enkephalin) and morphine on the myoelectrical pattern of the small bowel. Five conscious dogs were prepared with electrodes spaced 25 cm apart along the entire small intestine. Spike activity and slow waves were recorded with a Beckman Dynograph. Records were obtained in fasted conditions and following a meat meal or intravenous infusion of caerulein while animals received intravenous infusion of either met-enkephalin or morphine in various doses (range 10-160 microgram/kg . h). Met-enkephalin at a dose of 40 microgram/kg . h caused a significant decrease in spike activity and in the frequency of bursts of the interdigestive myoelectric complexes (IMC), whereas morphine almost doubled the frequency of the IMC. Met-enkephalin in dogs given food or infused with caerulein significantly decreased the fed-type spike activity of the small bowel, whereas morphine did not affect it. The effects of met-enkephalin and morphine on the intestinal myoelectrical pattern can be reversed by naloxone, an opioid antagonist, suggesting that they are mediated by separate opioid receptors.
脑啡肽是一种具有强大类阿片样作用的天然存在的肽，最近已在整个消化道组织中被检测到，但其作用尚不清楚。本研究旨在比较甲硫氨酸脑啡肽（蛋氨酸脑啡肽）和吗啡对小肠肌电活动模式的影响。对5只清醒的狗进行准备，沿整个小肠间隔25厘米放置电极。用贝克曼动态记录仪记录锋电位活动和慢波。在禁食条件下以及在给予肉餐或静脉注射蛙皮素后进行记录，同时动物以不同剂量（范围为10 - 160微克/千克·小时）静脉输注蛋氨酸脑啡肽或吗啡。剂量为40微克/千克·小时的蛋氨酸脑啡肽导致锋电位活动和消化间期肌电复合波（IMC）爆发频率显著降低，而吗啡使IMC频率几乎增加了一倍。给予食物或输注蛙皮素的狗体内的蛋氨酸脑啡肽显著降低了小肠的进食型锋电位活动，而吗啡对此没有影响。阿片受体拮抗剂纳洛酮可逆转蛋氨酸脑啡肽和吗啡对肠道肌电活动模式的影响，这表明它们是由不同的阿片受体介导的。
