Abstract: Objective To explore the effects of intrahippocampal injection of motilin on interdigestive migrating myoelectrical complex (MMC) of rat duodenum. Methods Adult SD rats of either sex were subjected to injection of 0.5 μl motilin (0.74 nmol/μl) through the guiding cannula stereotaxically implanted into the hippocampus previously. Interdigestive MMC of the duodenum was recorded by RM6240B multilead physiological recording system. Results After motilin injection into the hippocampus, duodenal MMC cycle was significantly shortened, but the amplitude and frequency of phase Ⅲ were increased without affecting the duration of phase Ⅲ. The effect of motilin injection into the hippocampus on MMC was completely abolished by subdiaphragmal vagotomy but not affected by intravenously injected atropine, phentolamine or propranolol. Anti-motilin serum could partly abolish the effects of motilin on MMC. Conclusions Motilin injection into the hippocampus have effects on the duration of duodenal MMC cycle and the amplitude and frequency of phase Ⅲ, which may rely on the effect of noncholinergic and nonadrenergic neurons on duodenal smooth muscle or the increase of local motilin via hippocampus-hypothalamus-brain stem-vagus pathway. The hippocampus plays an important role in duodenal MMC.