Kinins are small peptides rapidly produced following tissue injury that serve as important modulators of inflammation and pain. In the periphery, the actions of kinins include vasodilatation, increased vascular permeability, stimulation of immune cells, and induction of pain. Kinins in the central nervous system (CNS) appear to initiate a similar cascade of events leading to neural tissue damage as well as long lasting disturbances affecting blood-brain barrier function.¹

Kinins such as Bradykinin (BK), Lys-BK, desArg⁹-BK, and Lys-desArg⁹-BK exert their action via two distinct receptors: the B₁ Bradykinin receptor (BKRB1) and the B₂ Bradykinin receptor (BKRB2). The desArg⁹-BK and Lys-desArg⁹-BK peptides activate BKRB1 while BK and Lys-BK operate by activating BKRB2.² Both BKRB1 and BKRB2 are members of the seven-transmembrane domain, G protein-coupled receptor (GPCR) superfamily and share a common structure of seven putative transmembrane domains, an extracellular amino terminus, and a cytoplasmic carboxyl terminus.

Expression of BKRB1is inducible upon various types of tissue injury and by inflammatory mediators such as bacterial lipopolysaccharide (LPS) and cytokines. BKRB1 was long considered not to be expressed in healthy tissues. However, recent work has demonstrated a low level of expression of BKRB1 in the CNS of rodent and primates. In contrast, BKRB2 is constitutively expressed on various cell types.³ BKRB1 represents a potential therapeutic target for treatment of inflammatory disorders and cardiovascular diseases.