Jirón C, Romano M, Michelangeli F
J Membr Biol. 1984;80(2):119-34. doi: 10.1007/BF01868769.
The possibility of recycling, fusion and retrieval of membranes during the gastric secretory process was studied in isolated gastric mucosae of the toad Bufo marinus. Incorporation and efflux of 14C-inulin and horseradish peroxidase (HRP) into the tissue as well as transmission and freeze-fracture electron microscopic studies during the secretory cycle were done. HRP and 14C-inulin were incorporated into the tubulovesicular membrane system during the secreting-resting transition. Upon restimulation, markers were released towards the lumen. Marker efflux preceded onset of H+ secretion. Morphological transformations in the oxyntic cell as evidenced from transmission and freeze-fracture electron microscopy preceded acid secretion coinciding with marker efflux. At this time, images that have been associated with membrane fusion were found in the apical membranes of oxyntic cells. The results are consistent with a model where membrane area increases by a fusion mechanism at the expense of the tubulovesicular system. This transformation precedes the onset of H+ secretion. Upon cessation of the stimulus or inhibition, membranes are retrieved and the tubulovesicular system reformed. Retrieved membranes could be then reutilized in the next secretory cycle.
在海蟾蜍（Bufo marinus）的离体胃黏膜中，研究了胃分泌过程中膜的再循环、融合和回收的可能性。在分泌周期中，进行了14C-菊粉和辣根过氧化物酶（HRP）进入组织的摄取和流出以及透射和冷冻断裂电子显微镜研究。在分泌-静止转变期间，HRP和14C-菊粉被纳入微管泡膜系统。再次刺激时，标记物向管腔释放。标记物流出先于H+分泌开始。从透射和冷冻断裂电子显微镜观察到的壁细胞形态转变先于酸分泌，与标记物流出同时发生。此时，在壁细胞的顶端膜中发现了与膜融合相关的图像。结果与一个模型一致，即膜面积通过融合机制增加，以微管泡系统为代价。这种转变先于H+分泌开始。刺激停止或受到抑制时，膜被回收，微管泡系统重新形成。回收的膜随后可在下一个分泌周期中重新利用。
