Intestinal bicarbonate secretion in Amphiuma measured by pH stat in vitro: relationship with metabolism and transport of sodium and chloride ions.
Intestinal bicarbonate secretion in Amphiuma measured by pH stat in vitro: relationship with metabolism and transport of sodium and chloride ions.
复制标题
通过体外 pH 统计测量 Amphuma 肠道碳酸氢盐分泌：与钠离子和氯离子代谢和转运的关系。
DOI：
10.1113/jphysiol.1981.sp013717
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
White,JF
中科院分区：
文献类型：
--
作者：
Imon,MA;White,JF
1. 分离的Amphiuma小肠两侧暴露于缓冲或非缓冲介质中，在短路条件下产生与HCO3分泌一致的pH梯度（‐）。2. 当通过添加酸将未缓冲的粘膜培养基维持在pH 7.4时，在短路条件下（Isc），粘膜培养基的碱化速度为1‐2微当量/小时cm2，并通过缺氧、乙酰唑胺或去除CO2来减少碱化。3. HCO3（‐）分泌速率（JHCO3（‐））在黏膜pH高于或低于7.4时降低，并与浆膜HCO3（‐）成正比。4. JHCO3（‐）在无Na+（胆碱）和无Cl - （SO4（‐））培养基中以及暴露于苯乙烯sit后均减少。5. JHCO3（‐）‐Isc的差异与净Cl‐吸收一致。6. 暴露于浆膜HCO3（‐）后，组织阻力（Rt）升高，粘膜HCO3（‐）降低。7. 肠黏膜碳酸酐酶活性对乙氧恶唑胺敏感。8. 结论是HCO3（‐）分泌活跃，受细胞内碳酸酐酶活性的影响，并与Cl‐和可能的Na+吸收耦合。
1. Isolated Amphiuma small intestine exposed on both surfaces to buffered or unbuffered media generated gradients of pH under short‐circuited conditions consistent with secretion of HCO3(‐). 2. When unbuffered mucosal medium was maintained at pH 7.4 by addition of acid, alkalinization of the mucosal medium occurred at a rate of 1‐2 microequiv/hr cm2 under short‐circuit conditions (Isc) and was reduced by anoxia, acetazolamide or removal of CO2. 3. The rate of HCO3(‐) secretion (JHCO3(‐)) was reduced at a mucosal pH above or below 7.4 and was proportional to serosal HCO3(‐). 4. JHCO3(‐) was reduced in Na+‐free (choline) and Cl‐free (SO4(2‐) media and after exposure to the stilbene SITS. 5. The difference JHCO3(‐)‐‐Isc was consistent with net Cl‐ absorption. 6. The tissue resistance (Rt) was elevated upon exposure to serosal HCO3(‐) and lowered by mucosal HCO3(‐). 7. The intestinal mucosa exhibited carbonic anhydrase activity that was sensitive to ethoxazolamide. 8. It is concluded that HCO3(‐) secretion is active, influenced by intracellular carbonic anhydrase activity and coupled to Cl‐ and possibly Na+ absorption.