Its principal ligand is bradykinin, a 9 amino acid peptide generated in pathophysiologic conditions such as inflammation, trauma, burns, shock, and allergy.
B1 protein is synthesized by de novo following tissue injury and receptor binding leads to an increase in the cytosolic calcium ion concentration, ultimately resulting in chronic and acute inflammatory responses.
Gq stimulates phospholipase C to increase intracellular free calcium and Gi inhibits adenylate cyclase.
[2] Icatibant is a second generation B2 receptor antagonist which has undergone limited clinical trials in pain and inflammation.
FR 173657 is another orally active non-peptide B2 antagonist that has undergone limited trials as analgesic and antiinflammatory drug.