Li Z S, Fox-Threlkeld J E, Furness J B
Department of Anatomy & Cell Biology, University of Melbourne, Parkville, VIC, Australia.
J Anat. 1998 Jan;192 ( Pt 1)(Pt 1):107-17. doi: 10.1046/j.1469-7580.1998.19210107.x.
The presence of a cholinergic innervation of arterioles within the gut wall is suggested by pharmacological studies of nerve mediated vasodilatation, but attempts to identify nerve cells that give rise to cholinergic vasodilator fibres have yielded discrepant results. In the present work, antibodies to the vesicular acetylcholine transporter protein (VAChT) were used to investigate the relationships of immunoreactive nerve fibres to submucosal arterioles. Comparison was made with cerebral arteries, which are known to be cholinergically innervated. Double labelling immunohistochemical techniques revealed separate VAChT and tyrosine hydroxylase (TH) immunoreactive (IR) fibres innervating all sizes of arteries of the submucosa of the stomach, ileum, proximal colon, distal colon and rectum as well as the cerebral arteries. Arterioles of all digestive tract regions had greater densities of TH-IR innervation than VAChT-IR innervation. In the ileum, double labelling for VAChT-IR and VIP-IR or calretinin-IR showed more VAChT-IR than either VIP-IR or calretinin-IR fibres. Calretinin-IR and VAChT-IR were colocalised in a majority of calretinin-IR axons, but VIP-IR and VAChT-IR were not colocalised. All calretinin-IR nerve cells in submucous ganglia were immunoreactive for choline acetyltransferase, but only 1-2% of VIP-IR nerve cells were immunoreactive. Extrinsic denervation of the ileum did not alter the distribution of VAChT-IR fibres, but it eliminated TH-IR fibres. Removal of myenteric ganglia (myectomy) did not alter the distribution of fibres with VAChT or TH-IR. This work thus provides evidence for cholinergic innervation of intrinsic arterioles throughout the digestive tract and indicates that the fibres in the small intestine originate from submucosal nerve cells.
神经介导的血管舒张的药理学研究表明，肠壁内的小动脉存在胆碱能神经支配，但试图识别产生胆碱能血管舒张纤维的神经细胞却得出了不一致的结果。在本研究中，使用针对囊泡乙酰胆碱转运蛋白（VAChT）的抗体来研究免疫反应性神经纤维与黏膜下小动脉的关系。并与已知有胆碱能神经支配的脑动脉进行了比较。双重标记免疫组织化学技术显示，VAChT和酪氨酸羟化酶（TH）免疫反应性（IR）纤维分别支配胃、回肠、近端结肠、远端结肠和直肠以及脑动脉黏膜下层的各种大小的动脉。所有消化道区域的小动脉中，TH-IR神经支配的密度都高于VAChT-IR神经支配。在回肠中，VAChT-IR与VIP-IR或钙视网膜蛋白-IR的双重标记显示，VAChT-IR纤维比VIP-IR或钙视网膜蛋白-IR纤维更多。大多数钙视网膜蛋白-IR轴突中，钙视网膜蛋白-IR和VAChT-IR共定位，但VIP-IR和VAChT-IR不共定位。黏膜下神经节中的所有钙视网膜蛋白-IR神经细胞对胆碱乙酰转移酶呈免疫反应，但只有1-2%的VIP-IR神经细胞呈免疫反应。回肠的外在去神经支配并没有改变VAChT-IR纤维的分布，但消除了TH-IR纤维。切除肌间神经节（肌切除术）并没有改变VAChT或TH-IR纤维的分布。因此，这项研究为整个消化道内源性小动脉的胆碱能神经支配提供了证据，并表明小肠中的纤维起源于黏膜下神经细胞。
