title: Effect of antisecretory factor on Escherichia coli STa enterotoxin-induced alkalinisation of pig jejunal acid microclimate.
abstract: The effect of challenge by Escherichia coli STa enterotoxin on pig jejunal mucosal surface pH was investigated in vivo. Exposure to STa resulted in a rapid and reversible alkalinisation (P less than 0.001) of the jejunal mucosa from 6.27 +/- 0.11 (5) to 6.89 +/- 0.03 (5). This action of STa is probably mediated through cyclic 3'5'-guanosine monophosphate (cGMP) since the 8-bromo analogue of cGMP induced the same effect as that observed after STa challenge. The action of STa on mucosal pH was partially inhibited by pre-administration of an antisecretory factor (ASF) preparation. The action of 8-bromo cGMP was unchanged by the presence of ASF. This implies that ASF inhibition occurs during the early stages of STa action prior to stimulation of guanylate cyclase. This effect of STa on the pig jejunal mucosal surface pH, or acid microclimate, may explain why weak acid supplementation of oral rehydration solutions can be ineffective in certain types of diarrhoeal disease.
authors.affiliation: Department of Animal Physiology and Biochemistry, Royal Veterinary and Agricultural University, Frederiksberg C, Denmark.
authors.forename: G T
authors.initials: GT
authors.lastname: McEwan
authors.forename: B
authors.initials: B
authors.lastname: Schousboe
authors.forename: E
authors.initials: E
authors.lastname: Skadhauge
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D000930:Antidiarrheals / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000494:pharmacology*; D006152:Cyclic GMP / Q000378:metabolism; D004768:Enterotoxins / Q000494:pharmacology*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006162:Guanylate Cyclase / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D007583:Jejunum / Q000378:metabolism*; D008834:Microclimate; D009479:Neuropeptides / Q000494:pharmacology*; D010477:Perfusion; D013552:Swine
chemical_list: D000930:Antidiarrheals; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D009479:Neuropeptides; C049628:antisecretory factor; C034151:heat stable toxin (E coli); D015124:8-Bromo Cyclic Adenosine Monophosphate; D006162:Guanylate Cyclase; D006152:Cyclic GMP