杏仁核微量注射胃动素对十二指肠MMC的影响

目的探讨杏仁核微量注射胃动素对十二指肠消化间期移行性复合肌电活动(m igratingm yoe lectrica l com p lex,MM C)的影响及作用机理。方法采用中枢立体定位杏仁核微量注射,多道生理记录仪监测十二指肠MM C的方法,观察尾静脉给予阿托品(50μg/kg)、酚妥拉明(200μg/kg)、普萘洛尔(100μg/kg)及抗胃动素血清(1∶50)和膈下迷走神经切断术后,杏仁核微量注入胃动素(0.37 nm o l)对十二指肠MM C的影响。结果杏仁核微量注入胃动素可以使十二指肠MM C时相明显变短〔(586.3±42.0)s vs(694.0±36.2)s〕,峰电振幅增加〔(294.7±43.2)μV vs(255.1±23.5)μV〕,峰电频率增快〔(23.1±0.6)次/m in vs(18.2±0.4)次/m in〕,但对峰电时相无明显影响,峰电频率的变化率要大于峰电振幅的变化率〔(54.3±5.6)%vs(22.4±4.3)%〕;膈下迷走神经切断术可完全阻断杏仁核胃动素对十二指肠MM C的影响;阿托品、酚妥拉明、普萘洛尔不能阻断杏仁核胃动素对十二指肠MM C的影响;抗胃动素血清只能部分阻断杏仁核胃动素对十二指肠MM C的影响。结论杏仁核外源性胃动素可以使十二指肠MM C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,由非肾上腺素能非胆碱能神经元作用于十二指肠平滑肌或者促进胃动素的释放而实现的。

Effects of Intra-amygdaloid Injection of Motilin on the Interdigestive Migrating Myoelectrical Complex in Rat

OBJECTIVE: This study is undertaken to explore the effects of motilin in the amygdaloid nucleus on the interdigestive migrating myoelectrical complex (MMC) in rats. METHODS: Adult SD rats of either sex were used. 0.5 microL motilin (0.74 nmol/microL) was injected into the guide cannula which had been stereotaxically implanted into the amygdaloid nucleus. Then the MMC was recorded by an RM6240B multilead physiological recording system. Some rats also received subdiaphragmatic vagotomy, or intravenous injection of the M-cholinergic receptor antagonist atropine (50 microg/kg), the alpha-adrenergic receptor antagonist phentolamine (200 microg/kg), the beta-adrenergic receptor antagonist propranolol (100 microg/kg), the anti-motilin serum. RESULTS: After motilin was injected into the amygdaloid nucleus, the duodenal MMC cycle duration was decreased significantly, (586.3 +/- 42.0) vs. (694.0 +/- 36.2)s. However, the amplitude of phase III and the frequency of phase III was increased, (294.7 +/- 43.2) vs (255.1 +/- 23.5) microV and (23.1 +/- 0.6) vs. (18.2 +/- 0.4) bursts/min. But there were no effects on the duration of phase III. The percentage change in frequency of phase III was much greater than the percentage change in amplitude of phase III, (54.3 +/- 5.6) vs. (22.4 +/- 4.3). The effects of motilin in the amygdaloid nucleus on MMC were completely abolished by subdiaphragmatic vagotomy. The effects of motilin in the amygdaloid nucleus on MMC were not affected by intravenously injected atropine, phentolamine or propranolol. The anti-motilin serum partly abolished the effects of motilin in the amygdaloid nucleus on MMC. CONCLUSION: Motilin in the amygdaloid nucleus has effects on the duodenal MMC cycle duration, the amplitude of phase III and the frequency of phase III, all of which may rely on either the effects of noncholinergic and nonadrenergic neurons on duodenal smooth muscle, or the increase of local motilin via nucleus amygdalae-hypothalamus-brain stem-vagus pathway.