中文摘要：

目的探讨超级化激活环核苷酸调控的阳离子通道（hyperpolarization—activated cyclic nucleotide—gated channel 2，HCN2）阳性细胞在小鼠胃肠道肌间神经丛的分布。方法成年昆明小鼠的胃肠道，包括胃、小肠、结肠，制作全层铺片，免疫细胞化学染色HCN2阳性细胞、胆碱能神经及Cajal间质细胞（interstitial cells of Cajal，ICCs）。结果成年小鼠胃肠道肌间神经丛的HCN2阳性细胞成簇紧密排列，多数阳性细胞为DogiellI型神经元，阳性产物分布在细胞质和细胞膜，每个神经节内可见数个至数十个阳性细胞；神经突起虽可见HCN2阳性产物，但主要存在于较粗的突起。HCN2阳性神经元分布密度在胃肠道各段存在较大差异（P〈0．05）：以结肠密度最高，胃次之，小肠略低。利用胆碱能神经元标志物胆碱乙酰转移酶（ChAT）和ICCs的标志物（c-kit蛋白）分别与HCN2通道进行双重免疫染色，可见HCN2存在于胆碱能神经元，未见HCN2存在于ICCs的胞体，ICCs的突起与HCN2阳性神经元距离很近。结论HCN2离子通道广泛表达于肌间神经丛，主要表达于胆碱能神经元，可能参与该神经元调控胃肠神经活动、神经递质的释放以及胃肠功能的调节。

英文摘要：

Objective To investigate the distribution of hyperpolarization-activated cyclic nucleotidegated channel 2-positive cells （HCN2）, in the myenteric nerve plexus of gastrointestinal tract of mice. Methods Gastrointestinal tract samples, which included the stomach, small intestine and colon, from mature Kunming mice were collected for the preparation of whole-mount preparations, and then examined by immunocytochemistry for HCN2, cholinergic nerves and interstitial cells of Cajal （ICCs） with fluorescence microscopy and laser confocal microscopy. The markers of cholinergic nerves （CHAT） and ICCs （c-kit） were used to double-immunostaining with HCN2 channel. Results Most of HCN2-positive cells within the myenteric plexus of mature mice were Dogiel II type-neurons and positive products occurred on the cell membranes and cytoplasm. They often gathered in cluster in the ganglia, which contained several to dozens of IR cells for HCN2. IR products were seen on nervous process, but majority occurred on those which were thicker. The density of distribution for HCN2-positive cells in the gastrointestinal tract was different ： that of the colon was highest （ P 〈 0.05 ）, that of the stomach was lower than that of the colon （ P 〈 0.05 ）, and that of the small intestine was lowest （ P 〈 0.05 ）. HCN2 channel were found in the cholinergic nerves, although HCN2 channel not found in the soma of ICCs. The processes of ICCs were close to the HCN2-positive cells. Conclusion HCN2 channels are widely distributed in the myenteric nerve plexus, and primary expressed in the cholinergic nerves. HCN2 channels maybe involved in its regulation of gastrointestinal neural electrical activity, release of neurotransmitter and regulation of gastrointestinal function.