Effect of substituted benzimidazoles on acid secretion in isolated and enriched guinea pig parietal cells.

Abstract

SUMMARY The inhibitory effect of the three benzimidazole derivatives timoprazole, picoprazole, and omeprazole on histamine and dbcAMP stimulated 14C-aminopyrine accumulation (=H' secretion) has been studied in isolated and enriched guinea-pig parietal cells. fed guinea-pigs of either sex (300-400 g) were killed by a blow on the neck, the abdominal cavity was opened, the stomach excised, opened along the major curvature, rinsed in ice cold buffer (see below), and fixed on a cork plate. The fundic mucosa of two animals per preparation was scraped off and placed in 20 ml albumin free buffer (pH 7.4) solution of 370C which was subsequently incubated under gentle stirring with 0.5 g/l collagenase for 15 minutes to remove mucus and damaged superficial cells. The pH was kept constant at pH 7.4 by permanent autotitration with 5% NaHCO3.The mucosal fragments were subsequently centrifuged for one minute at 250xg at room temperature. The supernatant was discarded and the remaining tissue pieces were resuspended in 20 ml buffer containing 1 g/l albumin, 0.5 g/l collagenase, and 0-3 g/l pronase and incubated for a further 80 minutes at 37°C and pH 7.4 under constant gassing with 95% 02/5% C02. The incubation mixture was then filtered through a nylon cloth and centrifuged for 10 minutes at 400xg. The supernatant was discarded and the sediment was washed and recentrifuged twice with 30 ml enzyme free but albumin containing buffer at room temperature.

The sulphoxide moiety of substituted benzimidazoles is essential for inhibition of parietal cell K+/H+‐ATPase

“…The method of preparation of isolated and enriched guinea-pig parietal cells was in principle that of Soll (1978), with the modifications described in detail by Sewing et al (1983). Acid secretion in parietal cells was determined from cellular uptake of ['4C]-aminopyrine (Sewing et al, 1983).…”

“…Acid secretion in parietal cells was determined from cellular uptake of ['4C]-aminopyrine (Sewing et al, 1983). For inhibition studies, parietal cells were preincubated with the test compounds for 30 min at 22C.…”

“…In several in vitro preparations, such as isolated gastric mucosa of the guinea-pig (Sj6strand et al, 1978), isolated gastric glands of the rabbit (Wallmark et al, 1983) and enriched guinea-pig parietal cells (Sewing et al, 1983), these compounds inhibit H' secretion induced by histamine and dibutyryl cyclic AMP suggesting that they act on a step in the acid-secretory process, distal to the parietal cell receptor. Studies on the K+/H+-ATPase, which can be regarded as the proton pump in the secretory membrane of parietal cells have shown that substituted benzimidazoles inhibit both the release of inorganic phosphate from ATP and H' transport (Fellenius et al, 1981).…”

Effect of omeprazole on eicosanoid formation in and release from guinea‐pig gastric mucosal cells

“…Isolated and enriched parietal and mucous cells from the guinea-pig were prepared by a method similar to that of Soll (1978) with modifications described in detail by Sewing et al (1983 The activity of phospholipase A2 was determined by the release of ['4CJ-oleic acid from L-3-phosphatidylcholine, 1-palmitoyl-2-[1-'4q-oleoyl. The incubation mixture contained in a total volume of 0.5 ml the following components: 0.53 mM L-a-phosphatidyl-…”

Mechanism of gastric antisecretory effect of SCH 28080

“…Studies with guinea-pig isolated and enrichedparietal cells Isolated and enriched parietal cells from the guineapig were prepared as described by Sewing et al (1983 Beil & Sewing (1984). The method was modified in that the cells were isolated in the presence of 100 gM cimetidine and the cell separation process by the elutriation system was omitted.…”