Classification of kinin receptors

This minireview is divided into three parts: the first part refers to the characterization and classification of kinin receptors using agonists and antagonists in isolated tissues (classical pharmacology). Two kinin receptors have been considered on the basis of their distinct pharmacology, namely the B-1 receptor of the rabbit aorta (rank order of potency of agonists: LysdesArg(9)BK>desArg(9)BK greater than or equal to LysBK>BK; apparent affinities of antagonists Lys[Leu(8)]desArg(9)BK (pIC(50) 8.4)>[Leu(8)]desArg(9)BK (pIC(50) 7.4)>>>HOE 140, a B-2 receptor antagonist, pIC(50)<5.0), and the B-2 receptor of the rabbit jugular vein (potency of agonists: Lys-BK=BK>>>LysdesArg(9)BK=desArg(9)BK and HOE 140 (pIC(50) 9.0)>>>Lys[Leu(8)]desArg(9)BK, pIC(50)<5.0). The second part describes species-related B-1 receptor subtypes, demonstrated by different pharmacological profiles of agonists and antagonists: human, rabbit and pig subtypes (LysdesArg(9)BK>>desArg(9)BK and Lys[Leu(8)]desArg(9)BK>[Leu(8)]desArg(9)BK) and dog, rat, mouse and hamster B-1 receptors (desArg(9)BK = LysdesArg(9)BK and [Leu(8)]desArg(9)BK = Lys[Leu(8)]desArg(9)BK). Affinities of agonists and antagonists in some species (man, rabbit, pig) are significantly increased (at least 10-fold) by the presence of a Lys at their N-terminus. The last part describes species-related B-2 receptor subtypes supported by results obtained with non-peptide receptor agonists (FR 190997) and antagonists (FR 173657). While BK acts as a full agonist in man, rabbit and pig, FR 190997 behaves as a full agonist on human, as partial agonist on rabbit, and as pure antagonist on pig B-2 receptors, Various hypotheses are considered to interpret these findings.