In situ and constitutive analysis of peristaltic movement in the ureter

本研究的目的是鉴定起搏细胞，并对输尿管狭窄的发生机制进行综合分析。我们开发了一种使用宏观变焦显微镜的大鼠子宫盆腔制备物的原位Ca^2+成像技术。该技术清晰明亮的视野和平滑的缩放操作使我们能够搜索Ca^<2+>瞬变的上游，并容易地识别起搏区域。使用同样的技术，我们也可以成功地记录图像的di-4-ANEPPS，电压敏感染料。初始去极化发生在与Ca^2+瞬变开始的位置完全相同的位置。在更高的放大倍数下，我们可以观察到不仅是一个细胞，而是几个细胞同时增加了它们的细胞内Ca^<2+>浓度。每一次，它们的传播途径都略有不同。有趣的是，在肾盂的其他部分甚至在输尿管中也观察到了单个细胞自发的Ca^2+升高。它们与原始运动不同步，很少传播到邻近的细胞。在低浓度的间隙连接阻断剂庚醇的存在下，形成起搏区的细胞失去了它们的同步性和它们作为起搏器的功能。这些结果可能表明，通过缝隙连接的电活动的总和在起搏区的形成中发挥了重要作用。

The purpose of this study was to identify pacemaker cells and to perform integrated analysis on mechanisms of the ureteral peristalsis. We developed in situ Ca^<2+> imaging technique of the rat utero-pelvic preparation using a macro zoom microscope. The bright clear view and smooth zooming operation with this technique enabled us to search upstream of Ca^<2+> transient and to identify the pacemaker region easily. Using the same technique we could also successfully record image of di-4-ANEPPS, a voltage-sensitive dye. The initial depolarization occurred at the exactly same place as the Ca^<2+> transient began. With higher magnification, we could observe that not only one cell but several cells increased their intracellular Ca^<2+> concentration simultaneously. Their propagating pathway were slightly different every time. Interestingly spontaneous Ca^<2+> rises in single cells were observed in the other part of renal pelvis and even in the ureter. They are not synchronous to the pristaltic movement and rarely propagated to neighboring cells. In the presence of low concentration of heptanol, a gap junction blocker, the cells forming the pacemaker region lost their synchronism and their function as the pacemaker. These results might suggest that summation of electric activity via gap junctions played an important role in the formation of the pacemaker region.