Disruption of active zones in frog neuromuscular junctions following treatment with proteolytic enzymes.
Disruption of active zones in frog neuromuscular junctions following treatment with proteolytic enzymes.
复制标题
用蛋白水解酶处理后，青蛙神经肌肉接头的活性区被破坏。
DOI：
10.1007/bf01735378
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Ko,CP
中科院分区：
文献类型：
--
作者：
Nystrom,RR;Ko,CP
Frog neuromuscular junctions treated with proteolytic enzymes to remove the basal lamina were studied with freeze-fracture techniques in order to examine the influence of the basal lamina in the maintenance of active zone ultrastructure. The active zone is believed to be the site of transmitter release and has a unique membrane organization and location in the neuromuscular junction. After removal of the basal lamina by successive treatment of 0.01% collagenase and 0.1% protease for 1 h each, active zone disruption was observed. Some active zones became segmented, and some were also randomly located and oriented, but they still had normal double-row particle organization. Others contained only clusters of large intramembrane particles. These disorganized active zones were still functional as indicated by the presence of vesicle openings. Some enzyme-treated junctions were also exposed to the membrane cholesterol probe, filipin, to examine the expression of membrane lipid heterogeneity in disrupted active zones. As in normal active zones, filipin—sterol complexes were absent. The densities of background particles in the presynaptic membranes and of large particles thought to be acetylcholine receptors were not significantly altered by the enzyme treatment. Although a direct effect of the enzymes on active zone ultrastructure can not be totally excluded, the present work is consistent with a maintenance role of the basal lamina in active zone organization and location.
