Effects of motilin in the hippocampus on the interdigestive migrating motor complex in rats

摘要

Objective: To explore the effects of motilin in the hippocampus on the interdigestive migrating motor complex (MMC) in rats. Methods: Adult SD rats of either sex were used; 0.5 μl motilin (0.74 mmol/L) was injected into the guide cannula which was stereotaxically implanted into the hippocampus previously. Then the MMC was recorded by a RM6240B multilead physiological recording system. Results: (1)MMC characteristics of normal rats' duodenum; the frequency of phase Ⅲ was (18.1 ± 0.4) bursts/min; the amplitude of phase Ⅲ was (260.5 ± 42.3) μV; the duration of phase Ⅲ was (354.1 ± 21.6) s; MMC cycle duration was (690.2 ± 58.7)s. (2) After motilin was injected into the hippocampus, the duodenal MMC cycle duration was decreased significantly. However, the amplitude of phase Ⅲ and the frequency of phase Ⅲ were increased. But there were no effects on the duration of phase Ⅲ. Frequency of phase Ⅲ percentage change was much more than amplitude of phase Ⅲ percentage change (57.2 ± 2.8 vs 39.3 ± 5.2). (3) Effects of motilin in the hippocampus on MMC were completely abolished by subdi-aphragmal vagotomy. (4) Effects of motilin in the hippocampus on MMC were unaffected by intravenously injected atropine, phentolamine or propranolol. (5) The anti-motilin serum partly abolished the effects of motilin in the hippocampus on MMC. Conclusion: Motilin in the hippocampus has effects on the duodenal MMC cycle duration, the amplitude of phase Ⅲ and the frequency of phase Ⅲ. Motilin in the hippocampus plays an important role in duodenal MMC.