Bradykinin is the endogenous agonist for the bradykinin receptor and is a proinflammatory peptide. Bradykinin acts through two GPCRs, the B1 receptor, which is expressed as a result of tissue injury and has a role in chronic pain and inflammation, and the B2 receptor, which is constitutively expressed and is responsible for bradykinins vasodilatory role. Bradykinin has selectivity for B2 over B1 receptors. In pain, bradykinin sensitises TRPV1 receptors.
