Gourdie R G, Green C R, Severs N J, Anderson R H, Thompson R P
Department of Anatomy and Developmental Biology, University College London, England.
Circ Res. 1993 Feb;72(2):278-89. doi: 10.1161/01.res.72.2.278.
The gap-junctional proteins connexin43 and connexin42 have been shown to be expressed in the developing and mature avian heart, but their respective spatiotemporal distributions are unknown. In the present study, we have immunolocalized connexin42 in the conduction tissues of the adult avian heart (nonbranching bundle, bundle branches, and Purkinje fibers) and vascular endothelial cells. Connexin43 immunolabeling was confined to vascular smooth muscle. A novel microwave-based method was used to label connexin42 and connexin43 in the same tissue section. Neither connexin42 nor connexin43 was immunolocalized in working myocardium, atrioventricular node, and atrioventricular ring tissue of the bird heart. Although connexin42 first appeared in periarterial conduction myocytes and vascular endothelium at 9-10 embryonic days, the central conduction tissues, including the nonbranching bundle and proximal branches, remained immunonegative for connexin42 up until hatching (approximately 20 embryonic days). During the early postnatal period (1-14 days), connexin42 immunolabeling progressively spread up the bundle branches toward the nonbranching bundle. Connexin42 appeared uniformly distributed along the left bundle branch by 14 postnatal days. The distribution and spread of connexin42 immunoreactivity suggest that the emergence of specialized junctional contacts along ventricular fascicles occurs relatively late in heart development and coincides with the emergence of the chick from incubation within the egg.
缝隙连接蛋白连接蛋白43和连接蛋白42已被证明在发育中的和成熟的禽类心脏中表达，但其各自的时空分布尚不清楚。在本研究中，我们对连接蛋白42在成年禽类心脏的传导组织（非分支束、束支和浦肯野纤维）以及血管内皮细胞中进行了免疫定位。连接蛋白43的免疫标记仅限于血管平滑肌。我们使用了一种基于微波的新方法在同一组织切片中标记连接蛋白42和连接蛋白43。连接蛋白42和连接蛋白43在禽类心脏的工作心肌、房室结和房室环组织中均未进行免疫定位。尽管连接蛋白42在胚胎第9 - 10天首次出现在动脉周围传导心肌细胞和血管内皮中，但直到孵化（约胚胎第20天），包括非分支束和近端分支在内的中央传导组织对连接蛋白42仍保持免疫阴性。在出生后的早期阶段（1 - 14天），连接蛋白42的免疫标记逐渐沿束支向上扩散至非分支束。出生后14天时，连接蛋白42沿左束支呈均匀分布。连接蛋白42免疫反应性的分布和扩散表明，心室束上特化连接接触的出现相对较晚，与雏鸡从蛋中孵化出来的时间一致。
