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Updated: Aug 16, 2026
Gastrointestinal Motility Monitor (GIMM)
Published on: December 1, 2010
[Effects of intrahippocampal microinjection of motilin on interdigestive migrating myoelectrical complexes of rat
Mei Liu1, Lei Dong, Wen-yi Zhu
1Department of Gastroenterology, Second Hospital of Xi'an Jiaotong University, Xi'an 710004, China. maybelake@126.com
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 microl motilin (0.74 nmol/microl) 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.
Insights
Intrahippocampal motilin injection shortens the duodenal migrating myoelectrical complex (MMC) cycle in rats. This effect involves the vagus nerve, highlighting the hippocampus's role in regulating gut motility.
Area of Science:
- Neurogastroenterology
- Gastrointestinal Physiology
Context:
- The interdigestive migrating myoelectrical complex (MMC) is crucial for gut motility.
- The hippocampus's role in regulating gastrointestinal functions is increasingly recognized.
Purpose:
- To investigate the impact of direct hippocampal motilin administration on duodenal MMC in rats.
- To elucidate the neural pathways mediating these effects.
Summary:
- Intrahippocampal motilin injection in rats significantly reduced duodenal MMC cycle length.
- Increased amplitude and frequency of phase III were observed, independent of phase III duration.
- The observed effects were abolished by subdiaphragmal vagotomy, suggesting vagal nerve involvement.
- The action was not mediated by cholinergic or adrenergic pathways but potentially involves non-specific pathways or local motilin increase.
Impact:
- This study demonstrates a novel role for the hippocampus in modulating gastrointestinal motility via the motilin system.
- Findings suggest a hippocampus-brainstem-vagus pathway influencing duodenal MMC.
- Highlights the hippocampus as a potential target for managing motility disorders.
