de Laat S W, Tertoolen L G, Grimmelikhuijzen C J
Nature. 1980 Dec 25;288(5792):711-3. doi: 10.1038/288711a0.
Diffusion gradients of morphogens have been inferred as a basis for the control of morphogenesis in hydra, and morphogenetic substances have been found which, on the basis of their molecular weight (MW), should be able to pass gap junctions. There have been several reports of the presence of gap junctions between epithelial cells of hydra. However, until now, there has been no report published on whether these junctions enable the epithelial cells to exchange molecules of small molecular weight, as has been described in other organisms. Therefore we decided to investigate the communicative properties of the junctional membranes by electrophysiological methods and by intracellular-dye iontophoresis. We report here that no electrotonic coupling is detectable between epithelial cells of Hydra attenuata in: (1) intact animals, (2) head-regenerating animals, (3) cell re-aggregates, and (4) hydra that have become nervefree. Furthermore we show that epithelial cells are unable to exchange low-molecular weight fluorescent dyes.
形态发生素的扩散梯度已被推断为水螅形态发生控制的基础，并且已经发现了一些形态发生物质，基于它们的分子量（MW），应该能够通过间隙连接。有几篇报道称水螅上皮细胞之间存在间隙连接。然而，到目前为止，尚未有关于这些连接是否能使上皮细胞像在其他生物体中所描述的那样交换小分子分子量分子的报道。因此，我们决定通过电生理方法和细胞内染料离子电渗法来研究连接膜的通讯特性。我们在此报告，在以下几种情况下，无法检测到细弱水螅上皮细胞之间的电紧张偶联：（1）完整动物；（2）头部再生动物；（3）细胞重聚体；（4）已无神经的水螅。此外，我们还表明上皮细胞无法交换低分子量荧光染料。
