眶额叶区多巴胺对胃运动的影响及其机制研究

Effect and mechanisms of dopamine in orbitofrontal cortex on the regulation of gastric motility

通过大鼠眶额叶微量注射给药,记录胃内压(Intragastric pressure,IGP),观察胃运动变化的方法,研究了眶额叶多巴胺(dopamine,DA)对胃运动调节的神经机制.结果显示,眶额叶注射DA10μg,胃内压显著升高;眶额叶单独注射DA D1受体阻断剂SCH 2μg(SCH23390,SCH),胃内压降低.眶额叶注射SCH 2μg,能阻断DA升高胃内压的作用;眶额叶注射利陪酮(Risperidon)2μg,可升高胃内压,增强胃运动.但利陪酮却不能阻断DA升高胃内压的作用;切断双侧膈下迷走神经,眶额叶注射DA增加胃内压的作用被消除.以上各组中胃收缩频率均无明显变化.实验结果表明,眶额叶内DA能增大胃内压,增强胃运动,DA对胃内压及胃运动的增强作用主要是通过D1受体介导,经过迷走神经传出.

The effect and mechanisms of dopamine （DA） in orbitfrontal cortex （OFC） on regulation of the gastric motility were studied using microinjected in OFC and recording intragastric pressure （IGP）. The results show that the microinjection of dopamine 10 μg in OFC causes a significantly effect on increase in intragastric pressure, and SCH （SCI-I23390, SCH） 2 μg makes a significantly effect on decrease in intragastric pressure. SCH 2 μg abolishes the gastric excitatory response from DA. Risperidone 2μg can enhances intragastric pressure. Risperidone 2μg could not abolish the gastric excitatory response from DA. When vagus are cut off, intragastric pressure decrease caused by DA disappears. The frequencies of gastric motility does not significantly change,in all cases. The results suggest that dopamine in OFC could make an increase in intragastric pressure. This effect is transmitted via vagus. SCH as the dopaminergic D1 receptor agonist could abolish the gastric excitatory response from DA. Risperidone as the dopaminergic D2 receptor agonist could not abolish the gastric excitatory response from DA. The increase intragastric pressure caused by DA in OFC is principally mediated by Dopaminergic D1 receptor.