Ogata T
Department of Surgery, Kochi Medical School, Japan.
Histol Histopathol. 1997 Jul;12(3):739-54.
The oxyntic, or parietal cell has two characteristic membrane systems. The mammalian intracellular canaliculi are specialized networks of narrow channels lined with numerous microvilli. The other common to all oxyntic cells is the tubulovesicles, a system of tubules and vesicles. The tubulovesicular compartment is drastically depleted during maximal gastric acid secretion and this is coincident with an increase in the cell surface membrane area. A plausible explanation of this process is the fusion and transfer of tubulovesicular membranes to the plasma membrane. However, for many years there was no convincing evidence of the connections between these two membrane systems. How the tubulovesicular membranes transform into plasma membrane without demonstrable connections has been an enigma to electron microscopists. Recent ultra-high resolution scanning electron microscopic observation on the rat oxyntic cell treated with aldehyde-osmium-aldehyde method revealed that in the resting stage, the tubulovesicles were isolated spherical vesicles. But after tetragastrin stimulation, they were interconnected by slender connecting tubules forming a tubulovesicular network. Then this network was fused to the intracellular canaliculus at relatively few points. These connections between the tubulovesicles and luminal surface membrane was also demonstrated in the frog oxynticopeptic cells. In this review, these membrane transformations as well as changes of the H+/K(+)-ATPase, the lectin binding glycocalyx and the cytoskeleton during secretion will be illustrated and discussed.
壁细胞，即胃壁细胞，有两种独特的膜系统。哺乳动物的细胞内小管是由众多微绒毛排列的狭窄通道组成的特殊网络。所有壁细胞共有的另一种结构是微管泡系统，即由小管和小泡组成的系统。在胃酸分泌达到最大值时，微管泡区室会大量减少，这与细胞表面膜面积的增加同时发生。对这一过程一个合理的解释是微管泡膜与质膜的融合和转移。然而，多年来一直没有确凿的证据证明这两种膜系统之间的联系。在没有明显连接的情况下，微管泡膜如何转化为质膜一直是电子显微镜学家的一个谜。最近，用醛锇醛法处理的大鼠壁细胞的超高分辨率扫描电子显微镜观察显示，在静止期，微管泡是孤立的球形小泡。但在促胃液素刺激后，它们通过细长的连接小管相互连接，形成微管泡网络。然后这个网络在相对较少的点与细胞内小管融合。微管泡与腔表面膜之间的这些连接在青蛙壁主细胞中也得到了证实。在这篇综述中，将对这些膜的转变以及分泌过程中H+/K(+)-ATP酶、凝集素结合糖萼和细胞骨架的变化进行说明和讨论。
