Veenstra R D, Wang H Z, Westphale E M, Beyer E C
Department of Pharmacology, State University of New York Health Science Center, Syracuse 63110.
Circ Res. 1992 Nov;71(5):1277-83. doi: 10.1161/01.res.71.5.1277.
Multiple gap junction proteins (connexins) and channels have been identified in developing and adult heart. Functional expression of the three connexins found in chick heart (connexin42, connexin43, and connexin45) by stable transfection of communication-deficient neuro2A (N2A) cells revealed that all three connexin cDNAs are capable of forming physiologically distinct gap junctions that differ in their transjunctional voltage dependence and unitary channel conductances. The transjunctional voltage dependences of connexin45 and connexin42 closely resembled those of 4-day and 18-day embryonic chick heart gap junctions, respectively. The multiple channel conductances between 80 and 240 pS, including the predominant 160 pS channel, observed in embryonic chick heart were also common to connexin42. The expression of multiple gap junction channels with distinct conductance and regulatory properties within a given tissue may account for developmental changes in intercellular communication.
在发育中的心脏和成年心脏中已鉴定出多种间隙连接蛋白（连接蛋白）和通道。通过对缺乏通讯功能的神经2A（N2A）细胞进行稳定转染，发现鸡心脏中存在的三种连接蛋白（连接蛋白42、连接蛋白43和连接蛋白45）的功能表达表明，所有这三种连接蛋白cDNA都能够形成生理上不同的间隙连接，它们在跨连接电压依赖性和单位通道电导方面存在差异。连接蛋白45和连接蛋白42的跨连接电压依赖性分别与4日龄和18日龄胚胎鸡心脏间隙连接的跨连接电压依赖性密切相似。在胚胎鸡心脏中观察到的80至240 pS之间的多种通道电导，包括主要的160 pS通道，在连接蛋白42中也很常见。在给定组织内具有不同电导和调节特性的多种间隙连接通道的表达可能解释了细胞间通讯的发育变化。
