DISTINCT GAP JUNCTION PROTEIN PHENOTYPES IN CARDIAC TISSUES WITH DISPARATE CONDUCTION PROPERTIES
DISTINCT GAP JUNCTION PROTEIN PHENOTYPES IN CARDIAC TISSUES WITH DISPARATE CONDUCTION PROPERTIES
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DOI：
10.1016/0735-1097(94)90879-6
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发表时间：
1994-10-01
影响因子：
24
通讯作者：
SAFFITZ, JE
中科院分区：
文献类型：
--
作者：
DAVIS, LM;KANTER, HL;SAFFITZ, JE
目标。我们试图表征具有不同传导特性的犬心脏选定区域的连接蛋白表型，以确定连接蛋白表达的差异是否可能导致不同心脏组织中出现的细胞间电阻和传导速度的差异。缝隙连接连接心肌细胞，使动作电位得以传播。不同的连接蛋白形成具有不同电生理特性的细胞间通道。用连接蛋白26、连接蛋白31、连接蛋白32、连接蛋白37、连接蛋白40、连接蛋白43、连接蛋白45、连接蛋白46和连接蛋白50的探针与来自这些部位的信使核糖核酸(RNA)杂交，以确定哪些连接蛋白可能在窦房结、房室结以及房室心肌中表达。用连接蛋白40、连接蛋白43和连接蛋白45的单特异性抗体进行免疫组织化学染色，观察不同心肌组织冰冻切片中连接蛋白的分布。Northern印迹分析仅检测到连接蛋白40、连接蛋白43和连接蛋白45的信使RNA。免疫组织化学染色显示，窦房结和希氏束近端的交界处几乎不含连接蛋白43，但同时含有连接蛋白40和连接蛋白45。在远端希氏束和近端束支的缝隙连接处，连接蛋白40和连接蛋白43染色强烈，连接蛋白45染色较少。心房缝隙连接处连接蛋白Cx43、Cx40、Cx45表达丰富。Cx43、Cx45表达丰富，Cx40表达较少。虽然大多数心脏缝隙连接都含有连接蛋白40、连接蛋白43和连接蛋白45，但在不同传导特性的心脏组织中，每种连接蛋白的相对数量都有很大的差异。
Objectives. We sought to characterize the connexin phenotypes of selected regions of the canine heart with different conduction properties to determine whether variations in connexin expression might contribute to the differences in intercellular resistance and conduction velocity that occur in different cardiac tissues.Background. Gap junctions connect cardiac myocytes, allowing propagation of action potentials. Intercellular channels with different electrophysiologic properties are formed by different connexin proteins.Methods. To determine which connexins were likely to be expressed in the sinus node, atrioventricular (AV) node and atrial and ventricular myocardium, messenger ribonucleic acids (RNAs) from each of these sites were hybridized with probes for connexin26, connexin31, connexin32, connexin37, connexin40, connexin43, connexin45, connexin46 and connexin50. Immunostaining with monospecific antibodies to connexin40, connexin43 and connexin45 was used to delineate the distribution of connexins in frozen sections of these different cardiac tissues.Results. Only messenger RNAs coding for connexin40, connexin43 and connexin45 were detected by Northern blot analysis. By immunohistochemical staining, junctions in the sinus and AV nodes and proximal His bundle mere virtually devoid of connexin43 but contained both connexin40 and connexin45. Gap junctions in the distal His bundle and the proximal bundle branches stained intensely for connexin40 and connexin43 and to a lesser extent for connexin45. Atrial gap junctions showed abundant staining of connexin43, connexin40 and connexin45. Ventricular gap junctions were characterized by abundant staining of connexin43 and connexin45 and much less staining of connexin40.Conclusions. Although most cardiac gap junctions contain connexin40, connexin43 and connexin45, the relative amounts of each of these connexins vary considerably in cardiac tissues with different conduction properties.