Quantitative immunoelectron microscopic localization of (Na+,K+)ATPase in rat parotid gland.
Quantitative immunoelectron microscopic localization of (Na+,K+)ATPase in rat parotid gland.
复制标题
大鼠腮腺中 (Na ,K )ATP 酶的定量免疫电镜定位。
DOI：
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发表时间：
1987
影响因子：
3.2
通讯作者：
Y. Tashiro
中科院分区：
文献类型：
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作者：
T. Iwano;M. Akayama;A. Yamamoto;K. Omori;T. Kumazawa;Y. Tashiro
应用包埋后蛋白A-gold免疫电镜技术，对大鼠腮腺腺泡和导管细胞膜上（Na+，K+）ATP酶的分布进行了定量研究。在腺泡细胞中，ATP酶主要定位于基底外侧质膜上。一个小的，但显着量的（Na+，K+）ATP酶，然而，检测到的管腔质膜上，特别是在微绒毛区域的腺泡细胞;管腔膜上的表面密度约为三分之一的基底外侧膜。在导管细胞中，在基底外侧膜上，尤其是在质膜的基底内折处沿着，发现了许多金颗粒，而在管腔质膜上没有发现明显的金颗粒，表明ATP酶在导管细胞中呈单侧分布。我们认为，在腺泡细胞中，钠离子不仅被细胞旁转运，而且还被位于管腔质膜上的（Na+，K+）ATP酶主动转运到管腔空间中，并且水被被动转运到管腔空间以形成血浆样等渗初级唾液，而在导管细胞中，相同的离子被（Na+，K+）ATP酶选择性地再吸收到细胞内。在基底质膜的许多内折处发现大量的（沿着）K+ ATP酶，从而产生低渗唾液。
Distribution of (Na+,K+)ATPase on the cell membranes of acinar and duct cells of rat parotid gland was investigated quantitatively by immunoelectron microscopy using the post-embedding protein A-gold technique. In acinar cells, ATPase was localized predominantly on the basolateral plasma membranes. A small but significant amount of (Na+,K+)ATPase was, however, detected on the luminal plasma membranes, especially on the microvillar region of the acinar cells; the surface density on the luminal membrane was approximately one third of that on the basolateral membranes. In duct cells, many gold particles were found on the basolateral membrane, especially along the basal infoldings of the plasma membranes, whereas no significant gold particles were found on the luminal plasma membranes, suggesting unilateral distribution of ATPase in duct cells. We suggest that in acinar cells sodium ion is not only transported paracellularly but is also actively transported intracellularly into the luminal space by the (Na+,K+)ATPase located on the luminal plasma membranes, and that water is passively transported to the luminal space to form a plasma-like isotonic primary saliva, while in the duct cells the same ion is selectively re-absorbed intracellularly by (Na+,K+)ATPase found in abundance along the many infoldings of the basal plasma membranes, thus producing the hypotonic saliva.