RÉSUMÉ
Objective To observe the prokinetic effect of domperidone on esophagus and lower esophageal sphincter (LES), and compare its effect with that of mosapride and cisapride. Methods In vivo experiments: forty rats were divided into control, domperidone, mosapride, and eisapride groups. Strain gauges were planted in proximal esophagus, distal esophagus and LES to record the activities of esophagus and LES in conscious rat. In vitro experiments: in the thermostatic muscle bath, the prokinetic effect of domperidone, mosapride, and cisapride on the contractility of rat muscle strips from esophagus body and LES were recorded by tone-transducers. Results In vivo experiments, ① In the interdigestive period of resting conscious rats, only mild contraction activities were recoded in esophagus bodies. In LES, typical interdigestive migrating motor complex (MMC) with phase Ⅰ,Ⅱ,Ⅲ,and Ⅳ was recorded. The contraction amplitude of LES was much greater than esophagus body. ② Domperidone significantly enhanced the contraction of esophagus body and LES. The mean contraction amplitude of proximal esophagus, distal esophagus, and LES increased by 63.24%±7.17%, 75.54%±5.27%, and 85.81%±6.02%, respectively, compared with controls. The prokinetic effect showed a dose-effect relation. Mosapride at the same dosage increased the mean contraction amplitude of proximal esophagus, distal esophagus, and LES by 29. 71%±4.15%, 40.15%±3.30%, and 35.24%±5.36%, respectively, compared with controls. The prokinetic effects of mosapride on esophagus and LES were much less than domperidone. Cisapride at the same dosage increased the mean contraction amplitude of proximal esophagus, distal esophagus, and LES by 59.84%±6.55%, 70.11%±5.62%, and 75.13%± 5.10%, respectively, compared with controls. The prokinetic effects of cisapride were similar as domperidone. In vitro experiments. ① Domperidone perfusion could significantly increase the contraction of esophagus body and LES muscle strips by 87.74%±7.65% and 92.44±7.17%, respectively, compared with Krebs-Ringer (KR) solution perfuslon. Mosapride at the same dosage increased the mean contraction amplitude by 35.42%±5.02% and 31.12%±4.32%, respectively, compared with KR controls. The prokinetic effects of mosapride were much less than domperidone. Cisapride of the same dosage showed a similar prokinetic effect as domperidone. ② Atropine and tetrodotoxin could block the prokinetic effects of domperidone on esophagus and LES. Conclusions Domperidone can significantly enhance the esophagus body contraction and LES motility. The effects of domperidone are similar as cisapride and much greater than mosapride. The prokinetic effects of domperidone on esophagus and LES are not only through well-known dopaminergic receptor blockade, but also through the cholinergic nerves of the enteric nervous system.