Sodium-proton exchange in colon brush-border membranes.
Sodium-proton exchange in colon brush-border membranes.
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结肠刷状缘膜中的钠-质子交换。
DOI：
10.1152/ajpgi.1986.251.3.g382
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Hauri,HP
中科院分区：
文献类型：
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作者：
Binder,HJ;Stange,G;Murer,H;Stieger,B;Hauri,HP
通过基于形态学标准的方法从大鼠大肠的近端和远端段制备顶膜囊泡，并用于测定22 Na摄取。在这两种制剂中，向外定向的质子梯度刺激22 Na摄取。在近端结肠中，由介质渗透压增加引起的囊泡体积减少导致90 min时22 Na摄取减少;摄取的显著（50-60%）部分代表结合。初始摄取在10秒内呈线性，外推至零，表明囊外结合最小。初始吸收是介质Na浓度的饱和函数。在两种制剂中，0.1 mM NaCl的初始流入被阿米洛利（0.1-1.0 mM）、15 mM NaCl、15 mM LiCl和15 mM NH 4Cl抑制。从最初的22 Na流入的特点，我们得出结论，从近端和远端段的结肠细胞的顶膜包含一个Na-H交换与其他上皮细胞中描述的那些类似的属性。
Apical membrane vesicles were prepared from proximal and distal segments of the large intestine of the rat by a method based on morphological criteria and were used to determine 22Na uptake. In both preparations an outwardly directed proton gradient stimulated 22Na uptake. In proximal colon a decrease in vesicular volume induced by an increased media osmolarity led to diminished 22Na uptake at 90 min; a significant (50-60%) portion of uptake represented binding. Initial uptake was linear for 10 s and extrapolated through zero, indicating minimal extravesicular binding. Initial uptake was a saturable function of medium Na concentration. In both preparations initial influx of 0.1 mM NaCl was inhibited by amiloride (0.1-1.0 mM), 15 mM NaCl, 15 mM LiCl, and 15 mM NH4Cl. From the characteristics of the initial 22Na influx we conclude that the apical membrane from colonocytes of proximal and distal segments contains a Na-H exchange with properties similar to those described in other epithelia.