Schmauder-Chock E A, Chock S P
Department of Experimental Haematology, Armed Forces Radiobiology Research Institute, Bethesda, Maryland 20814-5145.
Histochem J. 1987 Aug;19(8):413-8. doi: 10.1007/BF01675751.
Secretory granules have been observed to swell during the process of exocytosis. Swelling is an indication of osmotic stress. The probable role of osmotic pressure in facilitating membrane fusion makes it necessary to determine whether granule membrane 'swelling' can occur prior to its fusion with the plasma membrane (pore formation) in the process of exocytosis. By subjecting adjacent thin and semi-thin sections of an activated granule to ultrastructural examination for membrane enlargement, and to metachromatic staining for verification of pore formation it is concluded that the perigranular membrane can indeed enlarge prior to pore formation. However, the degree of membrane enlargement can far exceed the limit of 2-3% stretching allowed under normal osmotic stress for a membrane bilayer. Such an extensive membrane enlargement, which takes place in the mechanism of exocytosis, cannot be achieved without being accompanied by the insertion of additional membrane.
在胞吐过程中观察到分泌颗粒会膨胀。膨胀是渗透压应激的一种表现。渗透压在促进膜融合中可能发挥的作用使得有必要确定在胞吐过程中颗粒膜与质膜融合（形成孔道）之前是否会发生“膨胀”。通过对活化颗粒的相邻超薄和半薄切片进行超微结构检查以观察膜的扩大，并进行异染染色以验证孔道的形成，得出结论：颗粒周围膜在孔道形成之前确实会扩大。然而，膜扩大的程度可能远远超过正常渗透压应激下膜双层允许的2 - 3%拉伸极限。在胞吐机制中发生的这种广泛的膜扩大，如果没有额外膜的插入是无法实现的。
