Stimulation of electrogenic chloride secretion by prostaglandin E2 in guinea‐pig isolated gastric mucosa.

Abstract

SUMMARY1. The effects of prostaglandin E2 (PGE2) on ion transport were investigated in guinea-pig isolated gastric mucosa.2. Under resting conditions the mucosa produced a short-circuit current (SCC), the majority of which could be attributed to electrogenic chloride secretion. This interpretation was confirmed by the dependence of the basal SCC on extracellular chloride, and inhibition by the chloride channel blocker, diphenylamine-2-carboxylate. The mucosa also exhibited low rates of acid secretion and of sodium and rubidium absorption.3. PGE2 stimulated an increase in net chloride secretion which was more than sufficient to account for the concomitant increase in SCC. As with the basal SCC, the SCC response to PGE2 was chloride dependent and inhibited by diphenylamine-2-carboxylate. PGE2 also significantly increased acid secretion and net rubidium absorption, but these changes were not sufficient to account for SCC.4. The H+-K+-ATPase inhibitor, omeprazole, inhibited basal and PGE2-stimulated acid secretion, but did not modify the effects the PGE2 on net chloride secretion, SCC or conductance, suggesting that these effects of PGE2 were not related to changes in gastric acid secretion.5. Both basal and PGE2-stimulated SCC were dependent on extracellular sodium and inhibited by ouabain, indicating the importance of a sodium gradient and the Na+-K+-ATPase in maintaining the electrogenic properties of the mucosa.6. These results are consistent with the view that PGE2 stimulates electrogenic chloride secretion in guinea-pig gastric mucosa, and provide an ionic basis for the stimulation of secretion of sodium and chloride by prostaglandins observed in mammalian gastric mucosa in vivo.

Prostaglandin E2 Produced by Entamoeba histolytica Signals via EP4 Receptor and Alters Claudin-4 to Increase Ion Permeability of Tight Junctions

“…20 To maintain charge balance in the lumen, sodium ions (cations) are pulled across the epithelium, also drawing water molecules and thus causing diarrhea. 19 PGE 2 is a potent colonic epithelial chloride ion secretagogue [21][22][23] ; however, it is not known whether it induces sodium ion flux across the epithelium. Colonic epithelial tight junctions (TJs) act as an important barrier for paracellular movement of macromolecules and ions across the epithelium.…”

RS 23597‐190: a potent and selective 5‐HT4 receptor antagonist

“…Male, Hartley guinea-pigs (300-350 g) were killed by CO2 asphyxiation and approximately 20 cm of distal ileum was removed starting 2.0 cm from the ileocaecal junction. Ileal mucosal sheets were prepared and mounted in Ussing chambers (window area 0.6 cm2) as described by Bunce & Spraggs (1989) and Scott et al (1992). The tissues were voltage-clamped at zero potential by passage of current using a voltage clamp amplifier (WPI, Sarasota, FL, U.S.A.) and the resulting short circuit current continuously recorded.…”

Transmucosal electrical resistance in rabbit isolated gastric mucosa during exposure to acid.

“…Thus, basal IS,, and that stimulated by PGE2, in the rabbit fundic mucosa is likely to be a reflection of electrogenic Clsecretion which is dependent upon a Na+ gradient generated by the Na'-K+-ATPase, and in this respect is similar to the guinea-pig (Bunce & Spraggs, 1988) and frog (Hogben, 1955) gastric mucosa. In other species, such as the rat (Jackson & Norris, 1985), pig and dog (Kuo & Shanbour, 1979), Na+ absorption contributes a larger proportion of the ISC.…”

“…Prostaglandins stimulate the non-parietal component of gastric secretion rich in NaCl (Gascoigne & Hirst, 1981;Smeaton & Hirst, 1984;Bunce, 1985). Although there is one report that prostaglandin increased the net absorption of Na+ in the dog gastric mucosa (Chaudhury & Jacobson, 1978), in both amphibian (Schiessel, Matthews, Barzilai, Merhav & Silen, 1980) and guinea-pig gastric mucosa (Bunce & Spraggs, 1988) there is good evidence for prostaglandin stimulation of electrogenic Cl-secretion. In the present study, we have examined the ability of prostaglandin E2 to influence the effect of luminal acid on electrical resistance.…”

“…We have re-examined this mechanism in light of the knowledge that in some species, the gastric mucosa is predominantly a Cl--secreting, rather than Na+-absorbing, epithelium; e.g. the frog (Hogben, 1955) and guinea-pig fundic mucosa (Bunce & Spraggs, 1988). We have further investigated the effect of various inhibitors of ion transport on the ability of the fundic mucosa to resist luminal acidification in order to gain insight into the underlying mechanisms.…”