The induction mechanisms for the paracellular transport upon stimulation of salivary secretion

为了阐明启动细胞旁转运的机制（估计腺体全部分泌液的60%以上来自细胞旁转运），将离体大鼠血管灌注的颌下腺置于共聚焦激光扫描显微镜下。我们观察到荧光染料（~500 Da）的通过，作为细胞旁运输的一个指标。在毒蕈碱或α 1-肾上腺素能刺激下引起液体分泌时，细胞内小管的荧光反应各不相同，但小管的平均荧光在30s内呈剂量依赖性地上升至平台。本项目得出的结论是，我们可以观察到荧光染料通过溶剂-阻力的压力依赖性细胞旁途径从细胞间隙进入腔腔，通过压力非依赖性途径的液体分泌仍有待进一步研究。打开过程持续30 s，与细胞收缩过程相似。

To clarify the mechanism to start the paracellular transport (more than 60% of the whole fluid secretion of the gland is estimated from paracellular route), the isolated vascularly perfused mandibular gland of rat was placed on the stage of the confocal laser-scanning microscope. We observed the passage of the fluorescent dye (~500 Da) as an indicator of paracellular transport. When the fluid secretion was induced by muscarinic or alpha1-adrenergic stimulation, the fluorescence of each intracellular canalliculi responded variously, but the average of canalliculus increased dose-dependently to the plateau within 30s. The present project led an conclusion that we can observe the entry of fluorescent dye from intercellular space to luminal space by pressure-dependent paracellular route by solvent-drag, and that the fluid secretion through pressure-independent route is still open for further studies. The process of opening continued for 30 s, which was similar to that of cell shrinkage.