Effects of Hypoxic Stimuli on Bronchopulmonary Neuroepithelial Bodies (Paraneuron)

支气管肺神经上皮小体（bronchopulpulmonary neuroepithelial bodies, neb）是由含有胺和肽的细胞簇组成的，广泛分布于人和动物肺的气道粘膜。在结构上，neb类似于化学感受器，如颈动脉体、味蕾，被认为是缺氧敏感的气道传感器。利用组织化学和组织免疫化学技术，阴性细胞的细胞质囊泡中含有5-羟色胺（5-HT）和肽样物质。在肺泡缺氧的情况下，neb将囊泡释放到细胞间隙。虽然这些细胞的氧感知机制和胞质囊泡释放的生理作用尚不清楚，但我们假设含有5-HT的囊泡的释放在肺血管收缩对吸入性缺氧的反应中起重要作用（缺氧肺血管收缩，HPV）。本研究采用离体大鼠肺灌注模型，研究了吸入麻醉剂、七氟醚和异氟醚以及低温对neb对缺氧或HPV反应的影响。我们还研究了局部液体通气（一种用于治疗严重呼吸衰竭的新型通气支持技术）对分离肺灌注模型中HPV的影响。吸入麻醉剂七氟醚和异氟醚对HPV的抑制作用均呈剂量依赖性。吸入浓度为4.0%的七氟醚和3.0%的异氟醚完全阻断了反应。但肺血管对缺氧的反应在停止吸入60分钟后恢复。麻醉剂对HPV的抑制作用是可逆的。低温也能抑制HPV。当灌注液温度低于30℃时，HPV被完全阻断。当灌注液温度升高到33℃以上时，HPV恢复。HPV不受全氟酮相关部分液体通气的影响。少

Bronchopulmonary neuroepithelial bodies (NEBs), composed of inervated clusters of amine-and peptide-containg cells, are widely distributed throughout the airway mucosa of human and animal lungs. Structuary, NEBs resemble chemoreceptors such as corotid bobies, taste buds and are thought to function as hypoxia senstive airway sensors. Using histochemical and histoimmunochemichal thechniques, NEGs have been shown to contain serotonine (5-HT) and peptidelike substances in their cytoplasmic vesicles. Under alveolar hypoxia, NEBs have been shown to release the vesicles to intercellular space. Though the mechanism of oxygen sensing by these cells and the physiological roles of the release of the cytoplasmic vesicles are unkown, we hypothesize that the release of vesicles which contain 5-HT play essential roles in the responses of pulmonary vascular constriction to inhalational hypoxia (hypoxic pulmonary vasoconstriction, HPV). In this study, we used isolated lung perfusion models of rats and … More investigated the effects of inhalational anesthetics, sevoflurane and isoflurane, and hypothermia on the responses of NEBs to hypoxia or HPV. We also examined the effects of partial liquid ventilation, a new ventilatory supporting thechnique for the managiment of sever respiratory failure, on HPV in the isolated lung perfusion models.Both inhalational anesthetics sevoflurane and isoflurane inhibited HPV dose dependently. Inhalational concentration of 4.0% sevoflurane and 3.0% isoflurane completely blocked the response. But the response of pulmonary vessels to hypoxia was recovered at 60 minutes after ceassation of inhalation. The inhibitory effects of the anesthetics on HPV were reversible. HPV was also inhibited by hypothermia. When the temprature of perfusate was below 30 degrees of centigrade, HPV was completely blocked. According to the increase of the temprature of perfusate above 33 degrees of Centigrade, HPV was restored. HPV was not affected by perflubrone associated partial liquid ventilation. Less