Demonstration and modification of intervillous pH profiles in rat small intestine in vitro

H. Daniel, C. Fett, A. Kratz

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37 Scopus citations


The intervillous pH profiles along the crypt villus axis in different regions of the rat small intestine were measured in vitro by using pH-sensitive liquid ion-exchanger microelectrodes. A characteristic pH profile was observed in the duodenum and jejunum. A region of low pH was detected in the upper parts of the villi (pH 6.65 ± 0.06 to 6.85 ± 0.07), whereas pH at the villus base was always higher. In the ileum no gradient was observed (pH 7.26 ± 0.05 to 7.31 ± 0.05). Preincubation of the tissue in situ with 10 mM theophylline for 1 h caused an increase in the villus base pH in the jejunum (pH 7.24 ± 0.04) and ileum (7.44 ± 0.04) followed by a subsequent increase of the pH in the upper part of the villi. These results indicate that the low pH in the upper intervillous space may be related to H+ secretion occurring from the mature enterocytes, whereas the crypt cells may secrete a rather neutral or slightly alkaline fluid. Alkaline secretion from the crypts may be increased by theophylline, which changes the levels of cyclic nucleotides in the mucosa.

Original languageEnglish
Pages (from-to)20/4
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Issue number4
StatePublished - 1989
Externally publishedYes


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