幽门括约肌接受迷走神经背侧运动核(DMV)的副交感神经支配。然而,对其高阶神经元和控制幽门的DMV神经元的细胞核知之甚少。本研究的目的是双重的。首先,确定高阶神经元和DMV之间的神经解剖学联系。这是通过使用注射到大鼠幽门圆环中的跨神经元伪狂犬病病毒PRV-152并检查这些动物的大脑进行PRV标记来进行的。第二,以确定DMV中在功能上控制幽门括约肌运动和张力的特定位点。对于这些研究,在尿烷麻醉的雄性大鼠中进行实验以评估DMV刺激对幽门活性的影响.将应变仪力传感器缝合到幽门上,以监测音调和运动性。将L-谷氨酸(500pmol/30nL)单侧显微注射到DMV的头端和尾区域。第一项研究的数据表明,DMV中出现了PRV标记的神经元,后脑中缝核,中脑Edinger-Westphal核,腹侧被盖区,外侧罗布,和弓形核。来自第二项研究的数据表明,将L-谷氨酸微注射到头端DMV中,会导致静脉内施用阿托品和同侧迷走神经切断术阻断幽门收缩。注射到尾DMV中的L-谷氨酸使幽门松弛。同侧迷走神经切断术消除了这种反应,但静脉内施用阿托品或L-NG-硝基精氨酸甲酯(L-NAME)却没有消除。这些发现确定了控制幽门括约肌的解剖学和功能性脑神经回路。我们的结果还表明,DMV的位点特异性刺激可以通过单独的迷走神经通路差异地影响幽门括约肌的活性。
The pyloric sphincter receives parasympathetic vagal innervation from the dorsal motor nucleus of the vagus (DMV). However, little is known about its higher-order neurons and the nuclei that engage the DMV neurons controlling the pylorus. The purpose of the present
study was twofold. First, to identify neuroanatomical connections between higher-order neurons and the
DMV. This was carried out by using the transneuronal pseudorabies virus PRV-152 injected into rat pylorus torus and examining the brains of these animals for PRV labeling. Second, to identify the specific sites within the DMV that functionally control the motility and tone of the pyloric sphincter. For these studies, experiments were performed to assess the effect of DMV stimulation on pylorus activity in urethane-anesthetized male rats. A strain gauge force transducer was sutured onto the pyloric tonus to monitor tone and motility. L-glutamate (500 pmol/30 nL) was microinjected unilaterally into the rostral and caudal areas of the DMV. Data from the first
study indicated that neurons labeled with PRV occurred in the
DMV, hindbrain raphe nuclei, midbrain Edinger-Westphal nucleus, ventral tegmental area, lateral habenula, and arcuate nucleus. Data from the second
study indicated that microinjected L-glutamate into the rostral
DMV results in contraction of the pylorus blocked by intravenously administered atropine and ipsilateral vagotomy. L-glutamate injected into the caudal
DMV relaxed the pylorus. This response was abolished by ipsilateral vagotomy but not by intravenously administered atropine or L-NG-nitroarginine methyl ester (L-NAME). These findings identify the anatomical and functional brain neurocircuitry involved in controlling the pyloric sphincter. Our results also show that site-specific stimulation of the DMV can differentially influence the activity of the pyloric sphincter by separate vagal nerve pathways.