大鼠杏仁核胃动素受体分布及其作用研究

Distribution and role of motilin receptor in the amygdala of rats

目的探讨大鼠杏仁核胃动素受体分布及杏仁核基底外侧核胃动素受体与外源性胃动素结合或者毁损后对十二指肠消化间期移行性复合肌电活动(MMC)的影响及其作用机制。方法采用免疫组织化学、中枢立体定位杏仁核微量注射、杏仁核毁损、多道生理记录仪监测十二指肠MMC的方法,探讨大鼠杏仁核胃动素受体的作用。结果杏仁核各亚核团都有胃动素受体分布,以杏仁内侧核分布最多;杏仁基底外侧核也有较多分布,后部多于前部;分布较少的核团是杏仁基底内侧核、杏仁中央核、杏仁基底外侧核;杏仁核基底外侧核胃动素受体与外源性胃动素结合后可以使十二指肠MMC时相变短,峰电振幅增加,峰电频率增快;膈下迷走神经切断术可完全阻断这种效应;阿托品、酚妥拉明、普萘洛尔不能阻断这种效应;抗胃动素血清只能部分阻断这种效应;杏仁基底外侧核核团毁损对十二指肠MMC影响不明显。结论杏仁核各亚核团都有胃动素受体分布,杏仁内侧核是胃动素受体分布最多的部位。杏仁核微量注射胃动素可以使十二指肠MMC的时相、峰电振幅和峰电频率发生变化,这种作用可能是通过杏仁核-下丘脑-脑干-迷走神经通路实现的,提示杏仁核胃动素受体在对十二指肠MMC的中枢性调节中发挥着重要作用。

Objective To explore the distribution and role ofmotilin receptor in the amygdala of rats. Methods The distribution ofmotilin receptor in the amygdala was detected by immunohistochemistry in adult SD rats of either sex. The duodenal interdigestive migrating myoelectric complex （MMC） was recorded and analyzed for investigating the role of motilin receptor in the amygdala. Results Motilin receptors were detected in the amygdala of rats. The medial amygdaloid nucleus contained the greatest amount of motilin receptors, which was also abound in the basolateral nucleus of the amygdala but less abundant in the basomedial nucleus of the amygdala, central amygdaloid nucleus and lateral amygdaloid nucleus. The binding of motilin receptors and motilin in the amygdala caused shortening of duodenal MMC cycle duration and increased amplitude and frequency of phase Ⅲ The effects were completely abolished by subdiaphragmal vagotomy but not by intravenous injection of atropine, phentolamine or propranolol, Anti-motilin serum partially abolished these effects, and destruction of the basolateral nucleus of the amygdala had no effects on duodenal MMC. Conclusions Motilin receptors are present in all the subnuclei of the amygdala. The effects of microinjection ofmotilin in the amygdala on duodenal MMC might rely on either the effects of noncholinergic and nonadrenergic neurons on the duodenal smooth muscle, or increase in local motilin via amygdala-hypothalamus-brain stem-vagus pathway, indicating the important role ofmotilin receptor in the amygdala in duodenal MMC regulation.