Kuramoto Hirofumi, Kadowaki Makoto
Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo, Kyoto, 606-8585, Japan.
Cell Tissue Res. 2006 Jun;324(3):361-7. doi: 10.1007/s00441-005-0124-x. Epub 2006 Feb 1.
To identify neurochemical phenotypes of esophageal myenteric neurons synaptically activated by vagal preganglionic efferents, we immunohistochemically detected the expression of Fos, an immediate early gene product, in whole-mount preparations of the entire esophagus of rats following electrical stimulation of the vagus nerves. When electrical stimulation was applied to either the cervical left (LVN) or right vagus nerve (RVN), neurons with nuclei showing Fos immunoreactivity (IR) were found to comprise approximately 10% of the total myenteric neurons in the entire esophagus. These neurons increased from the oral toward the gastric end of the esophagus, with the highest frequency in the abdominal portion of the esophagus. A significant difference was not found in the number of Fos neurons between the LVN-stimulated and RVN-stimulated esophagus. Double-immunolabeling showed that nitric oxide synthase (NOS)-IR occurred in most (86% and 84% in the LVN-stimulated and RVN-stimulated esophagus, respectively) of the Fos neurons in the entire esophagus. Furthermore, the stimulation of either of the vagus nerves resulted in high proportions (71%-90%) of Fos neurons with NOS-IR, with respect to the total Fos neurons in each segment, in the entire esophagus. However, a small proportion (8% and 7% in the LVN-stimulated and RVN-stimulated esophagus, respectively) of the Fos neurons in the esophagus exhibited choline acetyltransferase (ChAT)-IR. The occurrence-frequency of Fos neurons with ChAT-IR was less than 4% of the total Fos neurons in any segment of the LVN-stimulated and RVN-stimulated esophagus. Some of the Fos neurons with ChAT-IR appeared to be innervated by numerous varicose ChAT-positive nerve terminals. The present results showing that electrical stimulation of the vagus nerves induces a high proportion of Fos neurons with NOS-IR suggests the preferential activation of NOS neurons in the esophagus by vagal preganglionic efferents. This connectivity between the vagal efferents and intrinsic nitrergic neurons might be involved in inhibitory actions on esophageal motility.
为了识别由迷走神经节前传出纤维突触激活的食管肌间神经元的神经化学表型，我们通过免疫组织化学方法检测了即刻早期基因产物Fos在大鼠整个食管整装标本中的表达，该标本是在电刺激迷走神经后获取的。当对颈左侧迷走神经（LVN）或右侧迷走神经（RVN）进行电刺激时，发现细胞核呈现Fos免疫反应性（IR）的神经元约占整个食管中肌间神经元总数的10%。这些神经元从食管的口端向胃端增多，在食管腹部段的出现频率最高。在LVN刺激组和RVN刺激组的食管中，Fos神经元的数量未发现显著差异。双重免疫标记显示，一氧化氮合酶（NOS）-IR出现在整个食管中大多数（LVN刺激组和RVN刺激组分别为86%和84%）的Fos神经元中。此外，刺激任何一支迷走神经都会导致在整个食管的每个节段中，相对于该节段总的Fos神经元，具有NOS-IR的Fos神经元比例较高（71%-90%）。然而，食管中一小部分（LVN刺激组和RVN刺激组分别为8%和7%）的Fos神经元呈现胆碱乙酰转移酶（ChAT）-IR。在LVN刺激组和RVN刺激组食管的任何节段中，具有ChAT-IR的Fos神经元的出现频率均低于该节段总Fos神经元的4%。一些具有ChAT-IR的Fos神经元似乎被大量曲张的ChAT阳性神经末梢所支配。目前的结果表明，电刺激迷走神经会诱导高比例的具有NOS-IR的Fos神经元，这提示迷走神经节前传出纤维优先激活食管中的NOS神经元。迷走神经传出纤维与内在的含氮能神经元之间的这种联系可能参与对食管运动的抑制作用。
