Farraway L, Ball A K, Huizinga J D
Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
Am J Physiol. 1995 Jun;268(6 Pt 1):C1492-502. doi: 10.1152/ajpcell.1995.268.6.C1492.
Intercellular communication within the musculature of the canine colon was studied by examining the results of neurobiotin diffusion after injection of the tracer into smooth muscle cells at different locations within the muscle layer. Circular muscle at the submucosal surface, circular muscle adjacent to the myenteric plexus, and longitudinal muscle demonstrated different degrees of time-dependent tracer spread. At the submucosal surface, tracer spread was rapid, extensive, and unimpeded by connective tissue septa. At the myenteric side, tracer spread was also extensive but was much slower and confined to bundles of cells bordered by septa. In contrast to previous studies that suggest an absence of gap junctions at the myenteric side of the circular muscle, the neurobiotin spread indicates full metabolic coupling of all circular smooth muscle cells. Furthermore, in contrast to the belief that longitudinal muscle is completely devoid of gap junctions, tracer spread occurred between cells in this layer, although neurobiotin diffusion was very limited, nonuniform, and slow. In each area of the musculature studied, tracer spread was inhibited by octanol. When very long injection and wait times were implemented at the submucosal surface of the circular muscle, neurobiotin was observed to cross septa through the network of interstitial cells of Cajal, indicating that it is this network that provides communication between lamellae.
通过将示踪剂注射到肌层内不同位置的平滑肌细胞后，检测神经生物素扩散的结果，对犬结肠肌肉组织内的细胞间通讯进行了研究。黏膜下层表面的环行肌、与肌间神经丛相邻的环行肌以及纵行肌表现出不同程度的时间依赖性示踪剂扩散。在黏膜下层表面，示踪剂扩散迅速、广泛，且不受结缔组织间隔的阻碍。在肌间神经丛一侧，示踪剂扩散也很广泛，但速度慢得多，且局限于由间隔界定的细胞束。与之前表明环行肌肌间神经丛一侧不存在缝隙连接的研究相反，神经生物素的扩散表明所有环行平滑肌细胞完全代谢偶联。此外，与认为纵行肌完全没有缝隙连接的观点相反，尽管神经生物素扩散非常有限、不均匀且缓慢，但示踪剂仍在该层的细胞之间发生了扩散。在研究的肌肉组织的每个区域，示踪剂扩散都受到辛醇的抑制。当在环行肌的黏膜下层表面进行非常长的注射和等待时间时，观察到神经生物素通过 Cajal 间质细胞网络穿过间隔，这表明正是这个网络提供了薄片之间的通讯。
