In situ and constitutive analysis of peristaltic movement in the ureter

本研究的目的是鉴定起搏细胞，并对输尿管蠕动的机制进行综合分析。我们利用微缩显微镜建立了大鼠子宫-盆腔准备的原位钙成像技术。这项技术清晰的视野和流畅的变焦操作使我们能够搜索到钙瞬变的上游，并容易地识别起搏器区域。使用同样的技术，我们还成功地记录了电压敏感染料di-4-ANEPPS的图像。初始去极化发生在与钙离子瞬变开始完全相同的位置。在较高倍率下，我们可以观察到不只是一个细胞，而是多个细胞同时增加了细胞内钙离子浓度。它们的传播途径每次都略有不同。有趣的是，单细胞自发性Ca~(2+)&Gt~(2+)升高见于肾盆其他部位，甚至输尿管。它们与原生细胞的运动不同步，很少传播到邻近细胞。在低浓度的庚醇(一种缝隙连接阻滞剂)存在下，形成起搏器区域的细胞失去了它们的同步性和作为起搏器的功能。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.