Abstract:
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 (SCH23390, 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.
