Bradykinin stimulates prostaglandin E2 production and cyclooxygenase activity in equine nonglandular and glandular gastric mucosa in vitro.

The article discusses an experiment examining the influence of bradykinin (BK) on the production of prostaglandin E2 (PGE2) and cyclooxygenase (COX) activity in gastric mucosa tissues of horses. The experiment revealed that BK stimulated more PGE2 release from the tissues’ basal face compared to the apical side, suggesting a significant role for COX-1 pathways.

Characterizing and Quantifying PGE2 Output

• The study aimed to investigate the production of prostaglandin E2 (PGE2) by the nonglandular and glandular gastric mucosae of horses in an in vitro setting—outside a living organism.
• The researchers sought to better understand how PGE2 output is regulated by the gastric mucosae and the role of cyclooxygenase (COX) isoforms in this process.

Sensitivity of PGE2 Production to Bradykinin

• Bradykinin (BK) is a peptide that causes numerous effects in the body, such as blood vessel dilation. Its potential role in affecting the production of PGE2—a bioactive lipid that plays a significant role in inflammation and gastric protection—was explored in this study.
• In the experiment, the researchers exposed the gastric tissues to BK and then observed whether it influenced the production rate of PGE2.

Contribution of COX-1 and COX-2 Pathways

• The researchers wanted to identify whether the COX-1 and COX-2 pathways were involved in producing PGE2. COX-1 and COX-2 are enzymes that play a crucial role in the conversion of arachidonic acid into prostaglandins.
• Following the exposure to BK, the tissues were pretreated with a selective COX-2 inhibitor or a nonselective COX inhibitor to ascertain the contribution of these pathways to PGE2 production.

BK’s Influence on Electrogenic Ion Transport

• The potential influence of BK on electrogenic ion transport in gastric tissues was also investigated in the research. However, the study found that BK had no effect on electrophysiological parameters when tissues were mounted in Ussing chambers—a tool used to measure the transport of ions across biological membranes.

Resulting Findings

• The experiment revealed that BK induced PGE2 output from the basal face (the side facing the body’s interior) of both tissue types but not from the apical side (the surface layer).
• This increased PGE2 release could be inhibited with pretreatment with both the nonselective COX inhibitor and the COX-2 inhibitor, suggesting the involvement of the COX-1 pathway in particular.
• These findings hint that COX-1 plays a crucial role in PGE2 production from the basolateral faces of both nonglandular and glandular equine gastric mucosae in vitro.