Abstract
The normally acidic mucosal surface pH of 6.24 +/- 0.02(30) in rat proximal jejunum in vivo is effectively neutralised by 30 min exposure to heat-stable Escherichia coli (STa) enterotoxin (14 micrograms/ml) to 6.80 +/- 0.07 (n = 5) or to a forskolin/theophylline combination (1 mM:20 mM) to 7.10 +/- 0.07(7) while perfusion with Krebs-phosphate buffer alone without glucose left the mucosal surface pH unchanged at a pH of 6.21 +/- 0.02(9). Forskolin alone had no effect, and 20 mM theophylline moderately elevated the surface pH to 6.52 +/- 0.03(5). Theophylline, forskolin and their combination all elevated cAMP levels per mg tissue DNA above control values while STa enterotoxin was without effect. In contrast, all agents elevated cGMP levels per mg tissue DNA above control levels. These findings indicate that surface pH is only moderately affected by changes in cAMP levels and is affected to a much greater extent by altered cGMP levels.
Original language | English |
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Pages (from-to) | 325-31 |
Number of pages | 7 |
Journal | Biochimica et Biophysica Acta |
Volume | 971 |
Issue number | 3 |
Publication status | Published - 7 Oct 1988 |
Keywords
- Animals
- Bacterial Toxins
- Colforsin
- Cyclic AMP
- Cyclic GMP
- Electric Conductivity
- Enterotoxins
- Escherichia coli Proteins
- Hydrogen-Ion Concentration
- Intestinal Mucosa
- Jejunum
- Kinetics
- Rats
- Rats, Inbred Strains
- Reference Values
- Theophylline