Effects of rioprostil on bicarbonate secretion by guinea-pig gastric mucosa in vitro.
Spontaneous and prostaglandin-stimulated HCO3 secretions are studied in guinea-pig isolated gastric mucosa by means of pH-stat techniques. Antral mucosa exhibits a spontaneous HCO3- secretion of about 0.5 mumol/cm2h that is almost abolished by serosal addition of indomethacin (10(-5) mol/l). Fundic HCO3- secretion of the same magnitude is revealed upon suppression of acid secretion by serosal omeprazole (10(-5) mol/l). It is stimulated by serosal or mucosal addition of either PGE1, the synthetic primary alcohol analogue of PGE1, rioprostil, or dimethyl-PGE2. Effective concentrations range from 10(-4) to 10(-6) mol/l. Short-circuit current remains unchanged, arguing against involvement of electrogenic mechanisms of HCO3- secretion. Tissue conductance increases in the presence of all compounds tested, but only during luminal exposure to rioprostil does this increase go beyond that observed in time controls. Thus, enhanced HCO3- secretion seems to be due to cellular mechanisms rather than to a rise in passive (paracellular) HCO3- flow.
Petersen
K U
KU
Abteilung Pharmakologie, Medizinischen Fakultät, Rheinisch-Westfälischen Technischen Hochschule Aachen, FRG.
Winterhager
J M
JM
D015064:16,16-Dimethylprostaglandin E2 / Q000494:pharmacology; D000527:Alprostadil / Q000494:pharmacology; D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D001639:Bicarbonates / Q000378:metabolism*; D005753:Gastric Mucosa / Q000187:drug effects*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D011458:Prostaglandins E / Q000494:pharmacology*; D011465:Prostaglandins, Synthetic / Q000494:pharmacology; D016630:Rioprostil
D000897:Anti-Ulcer Agents; D001639:Bicarbonates; D011458:Prostaglandins E; D011465:Prostaglandins, Synthetic; D016630:Rioprostil; D000527:Alprostadil; D015064:16,16-Dimethylprostaglandin E2