Alpha and beta types of carbonic anhydrase-rich cells in turtle bladder.
Alpha and beta types of carbonic anhydrase-rich cells in turtle bladder.
复制标题
龟膀胱中富含碳酸酐酶的α型和β型细胞。
DOI：
10.1152/ajprenal.1985.249.4.f553
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Steinmetz,PR
中科院分区：
文献类型：
--
作者：
Stetson,DL;Steinmetz,PR
通过冷冻断裂和薄片电子显微镜研究了乌龟膀胱中富含碳酸酐酶 (CA) 的细胞群，该细胞负责 H+ 的分泌，也可能负责 HCO-3 的分泌。主要 CA 细胞类型（α 型）的顶膜的特征是微皱襞和细胞质侧的螺柱涂层；在冷冻断裂时，它含有密集的杆状膜内颗粒群。当在低CO2张力下固定时，α细胞的顶膜面积减少；其表面有微皱和微绒毛，顶端细胞质含有许多带有棒状颗粒和柱状颗粒的囊泡。另一种（β型）CA细胞的顶膜的特征是有许多单独的微绒毛，没有微皱襞，并且相对缺乏杆状颗粒和柱。相反，β细胞的基底外侧膜上含有螺柱和杆状颗粒。 β CA 细胞的超微结构和频率不受 CO2 张力变化的影响。我们认为α细胞负责H+的分泌。 β 细胞中膜元件极性的逆转以及未能通过其顶膜放大来响应 CO2 与 HCO-3 分泌中的作用一致。
The carbonic anhydrase-rich (CA) cell population of the turtle urinary bladder, which is responsible for the secretion of H+ and probably of HCO-3, was studied by freeze-fracture and thin-section electron microscopy. The apical membrane of the major CA cell type (alpha type) was characterized by microplicae and by a coat of studs on its cytoplasmic side; on freeze-fracture, it contained a dense population of rod-shaped intra-membrane particles. When fixed at low CO2 tension, the apical membrane area of the alpha cell was reduced; its surface displayed microplicae as well as microvilli, and the apical cytoplasm contained many vesicles with rod-shaped particles and studs. The apical membrane of the other (beta type) CA cell was characterized by numerous individual microvilli without microplicae and by a relative absence of rod-shaped particles and studs. Instead, the beta cell contained studs and rod-shaped particles in its basolateral membrane. The ultrastructure and frequency of the beta CA cell were not affected by changes in CO2 tension. We suggest that the alpha cell is responsible for H+ secretion. The reversal of the polarity of the membrane elements in the beta cell and failure to respond to CO2 with amplification of its apical membrane are consistent with a role in HCO-3 secretion.