THE EFFECT OF LOW MUCOSAL PH ON SODIUM AND CHLORIDE MOVEMENT ACROSS THE ISOLATED RUMEN MUCOSA OF SHEEP
THE EFFECT OF LOW MUCOSAL PH ON SODIUM AND CHLORIDE MOVEMENT ACROSS THE ISOLATED RUMEN MUCOSA OF SHEEP
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DOI：
10.1113/expphysiol.1989.sp003237
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发表时间：
1989-01-01
影响因子：
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通讯作者：
MARTENS, H
中科院分区：
文献类型：
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作者：
GAEBEL, G;BELL, M;MARTENS, H
采用Ussing小室技术对绵羊瘤胃粘膜进行了体外研究。通过加入盐酸改变了粘膜溶液的pH值。使用22Na和36Cl，在瘤胃粘膜pH值分别为7.4和5.5的短路和电压钳制条件下，测量了钠和氯化物的单向通量。降低粘膜pH值至5.5可引起短路电流(ISC)迅速下降。电导(GT)在ISC下降约10min后增加。在pH为5.5时，Na+和Cl-在粘膜到浆膜间的移动减少，从而导致净转运减少。这些改变在粘膜酸化30分钟后可见。120分钟后开始增强。进一步的研究表明，钳制跨壁电位差(20 MV)对酸化上皮中Na+和Cl-转运的影响仅略大。光镜和电子显微镜显示，酸暴露后细胞肿胀，尤其是线粒体肿胀。这些数据表明，降低粘膜pH会引起跨上皮钠和氯离子转运的改变。我们提出了对细胞运输机制的主要影响。
Isolated sheets of sheep rumen mucosa were studied in vitro by using the Ussing chamber technique. The pH of the mucosal solution was altered by adding HCl. Using 22Na and 36Cl unidirectional fluxes of sodium and chloride were measured across the short-circuited and voltage-clamped rumen mucosa at mucosal pH 7.4 and 5.5. Lowering mucosal pH to 5.5 caused a rapid decline in the short-circuit current (Isc). The conductance (Gt) increased about 10 min after the drop in Isc. At pH 5.5, mucosal-to-serosal movement of Na+ and Cl- was decreased thus leading to a decreased net transport. These alterations were seen 30 min after mucosal acidification. They were intensified 120 min thereafter. Further studies showed that a clamped transmural potential difference (20 mV) influenced Na+ and Cl- transport only slightly more in acidified epithelia. Light and electron microscopy showed a swelling of the cells and especially of their mitochondria after acid exposure. These data indicate that lowering mucosal pH causes alterations in transepithelial Na+ and Cl- transport. We suggest a predominant effect on cellular transport mechanisms.