Bradykinin is also thought to be the cause of the dry cough in some patients on angiotensin-converting enzyme (ACE) inhibitor drugs. It is thought that bradykinin is converted to inactive metabolites by ACE, therefore inhibition of this enzyme leads to increased levels of bradykinin, which causes a dry cough via bronchoconstriction. This refractory cough is a common cause for stopping ACE inhibitor therapy, in which case angiotensin II receptor antagonists (ARBs) are the next line of treatment.
Overactivation of bradykinin is thought to play a role in a rare disease called hereditary angioedema, formerly known as hereditary angio-neurotic edema.
Initial secretion of bradykinin post-natally causes constriction and eventual atrophy of the ductus arteriosus, forming the ligamentum arteriosum between the pulmonary trunk and aortic arch.
The B1 receptor (also called bradykinin receptor B1) is expressed only as a result of tissue injury, and is presumed to play a role in chronic pain. This receptor has been also described to play a role in inflammation. Most recently, it has been shown that the kinin B1 receptor recruits neutrophil via the chemokine CXCL5 production. Moreover, endothelial cells have been described as a potential source for this B1 receptor-CXCL5 pathway.
The B2 receptor is constitutively expressed and participates in bradykinin's vasodilatory role.
The kinin B1 and B2 receptors belong to G protein coupled receptor (GPCR) family.
The practical importance of the discovery of bradykinin became apparent when one of his collaborators at the Medical School of Ribeirão Preto at the University of São Paulo, Dr. Sérgio Henrique Ferreira, discovered a bradykinin-potentiating factor (BPF) in the bothropic venom, which increases powerfully both the duration and magnitude of its effects on vasodilation and the consequent fall in blood pressure. On the basis of this finding, Squibb scientists developed the first of a new generation of highly-effective anti-hypertensive drugs, the so-called ACE inhibitors, such as captopril (trademarked Capoten).
Currently, bradykinin inhibitors (antagonists) are being developed as potential therapies for hereditary angioedema. Icatibant is one such inhibitor. Additional bradykinin inhibitors exist. It has long been known in animal studies that bromelain, a substance obtained from the stems and leaves of the pineapple plant, suppresses trauma-induced swelling caused by the release of bradykinin into the bloodstream and tissues. Other substances that act as bradykinin inhibitors include aloe and polyphenols, substances found in red wine and green tea.
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^Kuoppala A, Lindstedt KA, Saarinen J, Kovanen PT, Kokkonen JO (April 2000). "Inactivation of bradykinin by angiotensin-converting enzyme and by carboxypeptidase N in human plasma". Am. J. Physiol. Heart Circ. Physiol.278 (4): H1069–74. PMID10749699.
^Duchene J, Lecomte F, Ahmed S, Cayla C, Pesquero J, Bader M, Perretti M, Ahluwalia A (October 2007). "A novel inflammatory pathway involved in leukocyte recruitment: role for the kinin B1 receptor and the chemokine CXCL5". J. Immunol.179 (7): 4849–56. doi:10.4049/jimmunol.179.7.4849. PMID17878384.
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