Bradykinin B2 receptor as a potential therapeutic target

Kinins are peptide hormones that exert pathophysiological as well as pronounced beneficial physiological effects, mainly by stimulation of bradykinin (BK) B(2) receptors. Owing to the strong proinflammatory properties of kinins resulting from vasodilation, plasma extravasation, activation of mast cells, fibroblasts and macrophages, stimulation of sensory neurons, and the release of nitric oxide, prostaglandins, leukotrienes and cytokines, kinins are believed to play an important role in a variety of inflammatory diseases and pain. Beneficial effects of BK B(2) receptor antagonists in perennial rhinitis, asthma and brain edema have already been shown in clinical trials. Recently, the potential therapeutic utility of BK B(2) receptor antagonists has been extended by the discovery of orally active, nonpeptide BK B(2) receptor antagonists and the identification of novel indications for their use. On the other hand, kinins also have been identified as potent antihypertensive and organ-protective peptides. They have been shown to have vasodilatory, antihypertrophic, antiaggregatory and fibrinolytic effects due to the BK B(2) receptor-mediated release of the autacoids nitric oxide, prostacyclin and tissue plasminogen activator. A recent finding is that kinins are also involved in ischemic preconditioning. Orally active, nonpeptide BK B(2) receptor agonists as potential novel therapeutic agents in cardiovascular medicine have also been identified. In conclusion, interaction with the BK B(2) receptor by either its blockade or its stimulation offers promising therapeutic approaches. BK B(2) receptor antagonists may prove to be useful in the treatment of asthma, rhinitis, arthritis, colitis, pancreatitis, sepsis, edema, tissue injury, pain and possibly infections, hepatorenal syndrome, Alzheimer's disease and lung cancer. BK B(2) receptor agonists have potential in the treatment of cardiovascular diseases like hypertension, cardiac hypertrophy, restenosis and myocardial infarction and diabetic disorders.