van Kempen M J, Jongsma H J
Department of Medical Physiology and Sports Medicine, Utrecht University, The Netherlands.
Histochem Cell Biol. 1999 Dec;112(6):479-86. doi: 10.1007/s004180050432.
Intercellular communication between cells of the vessel wall is established by a combination of diffusion and convection of humoral and endothelial factors in the extracellular fluid or by direct intercellular contacts present in the form of gap junctions composed of proteins called connexins. At least connexin (Cx)37, Cx40 and Cx43 are expressed in the vessel wall, but disparate findings with regard to the cell specific localisation of connexins in the vasculature indicate that the distribution of connexins may be species and vessel specific. Moreover, differences in expression exist between cells in culture and tissue sections. We performed an inventory immunohistochemical study on the localisation of Cx37, Cx40 and Cx43 on tissue sections of the bovine, micropig and rat aorta and coronary system, which represent morphologically and functionally different types of vessels in the arterial system. We could observe Cx40 labelling most commonly, although with various intensities, between endothelial and smooth muscle cells of the species studied, with the exception of rat aortic smooth muscle cells. The distribution of Cx43 is more differentiated and mostly confined to smooth muscle cells, although it can be detected scarcely between endothelial cells. Cx37, when detectable, is predominantly expressed between endothelial cells in a heterogeneous pattern. We conclude that Cx40 is the constitutive vascular gap junction protein in situ and guarantees cell coupling between cells in the vessel wall. The differentiated distribution of both Cx37 and Cx43 suggests they are involved in more dynamic processes.
血管壁细胞间的通讯是通过细胞外液中体液因子和内皮因子的扩散与对流组合建立的，或者是通过以连接蛋白构成的缝隙连接形式存在的直接细胞间接触建立的。至少连接蛋白（Cx）37、Cx40和Cx43在血管壁中表达，但关于连接蛋白在脉管系统中细胞特异性定位的不同研究结果表明，连接蛋白的分布可能具有物种和血管特异性。此外，培养细胞和组织切片中的表达也存在差异。我们对牛、小型猪和大鼠主动脉及冠状动脉系统的组织切片进行了一项关于Cx37、Cx40和Cx43定位的免疫组织化学研究，这些组织代表了动脉系统中形态和功能不同类型的血管。在所研究的物种中，除大鼠主动脉平滑肌细胞外，我们最常观察到Cx40标记在内皮细胞和平滑肌细胞之间，尽管强度各异。Cx43的分布更具差异性，主要局限于平滑肌细胞，尽管在内皮细胞之间几乎检测不到。Cx37在可检测到时，主要以异质性模式在内皮细胞之间表达。我们得出结论，Cx40是原位组成性血管缝隙连接蛋白，保证了血管壁细胞之间的细胞偶联。Cx37和Cx43的差异分布表明它们参与了更动态的过程。
