Bradykinin
Also known as: BK, kinin, bradykinin 1-9
Bradykinin is a nine-amino-acid peptide produced when kallikrein enzymes release it from its precursor, kininogen. It is a key signaling molecule in the body, involved in dilating blood vessels, increasing vascular permeability, and mediating pain and inflammation. It is rapidly degraded by enzymes, primarily angiotensin-converting enzyme (ACE), which limits its presence in the bloodstream.
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Overview
Chemical compound
Bradykinin (BK) (from Greek brady- 'slow' + -kinin, kīn(eîn) 'to move') is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor, and induces smooth muscle constraction via prostaglandin F2. Bradykinin consists of nine amino acids, and is a physiologically and pharmacologically active peptide of the kinin group of proteins.
Mechanism of Action
Bradykinin interacts with two G protein-coupled receptors: the B2 receptor, normally present in tissues, and the B1 receptor, which is expressed during inflammation. Activation of the B2 receptor results in vessel dilation, increased vascular permeability, and pain sensitization. Since ACE degrades bradykinin, ACE inhibitors can lead to its accumulation, which has been associated with side effects such as cough and angioedema as noted in clinical research.
Research History
Bradykinin was discovered in 1949 by Maurício Rocha e Silva and colleagues in Brazil, who observed that snake venom acting on blood plasma released a substance that slowly contracted smooth muscle, leading to its naming (bradys, slow; kinein, to move). It is a crucial component of the kallikrein-kinin system and continues to be a focal point in inflammation research. Modern studies also address its role in differentiating between bradykinin-driven and histamine-driven angioedema in emergency medicine.
What Researchers Are Saying
Community Reports - Not Medical Advice
The following is aggregated from public forums, Reddit, and research communities. These are anecdotal reports from researchers only - not verified clinical data and not a recommendation of any kind.
Bradykinin (also known as BK, kinin) is studied within the tissue repair and recovery research community. Vasoactive nonapeptide that mediates vasodilation, inflammation, and pain; studied in cardiovascular and pain research.
Last updated October 28, 2026
Research status: active. Bradykinin appears across tissue repair and recovery research forums and academic literature. Researchers note this compound falls in the tissue repair category.
Last updated October 28, 2026
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