Bradykinin

The physiological and pathological effects of the nonapeptide bradykinin (BK) are mediated via the activation of at least two types of bradykinin receptors termed B1 and B2. The B2 type is the most prevalent under physiological conditions and is preferentially activated by BK. The B1 type is selectively activated by des-Arg9-BK and seems to be greatly induced in some pathological states. Both B1 and B2 bradykinin receptors have had their cDNAs cloned and belong to the seven transmembrane coupled G-protein receptor family. BK receptor activation stimulates the transduction pathways leading to the generation of different second messengers (Ca2+, prostaglandins, NO, cGMP). It is suggested that bradykinin receptors are involved in various different physiological and physiopathological mechanisms such as the control of blood pressure and cardiovascular functions, the inflammatory reaction (allergy, asthma, oedema). Therefore it appears that bradykinin receptors activation can be involved in beneficial and deleterious effects and thus the development of both long lasting agonists and antagonists are of therapeutical interest.