Bradykinin Receptor Antagonists Containing N-Substituted Amino Acids: <i>In Vitro</i> and <i>in Vivo</i> B<sub>2</sub> and B<sub>1</sub> Receptor Antagonist Activity
作者:Val S. Goodfellow、Manoj V. Marathe、Karen G. Kuhlman、Timothy D. Fitzpatrick、David Cuadrado、Wendy Hanson、John S. Zuzack、Sherman E. Ross、Maciej Wieczorek、Michael Burkard、Eric T. Whalley
DOI:10.1021/jm950716i
日期:1996.1.1
We report a systematic probing of the structural requirements of the bradykinin (BK) type 2 (B-2) receptor for antagonist activity by incorporating N-Alkyl-amino acid residues at positions 7 and 8 of a potent antagonist sequence. Compound 1 (D-Arg(0)-Arg(1)-Pro(2)-Hyp(3)-Gly(4)-Thi(5)-Ser(6)- D-Tic(7)-N-Chg(8)-Arg(9), CP-0597)(1,2) is a potent (pA(2) = 9.3, rat uterus; pK(i) = 9.62, binding, human receptor clone) Bz receptor antagonist devoid of in vitro B-1 antagonist activity (rabbit aorta). Compound 1 exhibits high potency (ED(50) = 29.2 pmol/kg/min, iv, rabbit) and duration of action when tested in models for in vivo B-2 antagonist activity. Although devoid of activity in a classic B-1 isolated tissue assay, B-1 antagonist activity for 1 was demonstrated in vivo, in a LPS-treated, inducible BK1 receptor rabbit blood pressure model (ED(50) = 1.7 nmol/kg/min). D-Arg(0) of 1 can be formally replaced by an achiral arginine surrogate, without significant loss in antagonist potency on rat uterus (compound 11, B-2 pA(2) = 9.1). Antagonist 13 (Hyp(2), NChg(8)), pK(i) = 10.2, and agonist 4 (N-methylcyclohexyl-Gly(8)), pK(i) = 10.1, also exhibited substantial binding to guinea pig ileum membrane receptors as well as a human Bz receptor clone. Very minor structural changes in the N-alkyl amino acid residues in positions 7 and 8 can modify the activity of this class of compounds from being extremely potent antagonists to tight binding partial or full agonists. These studies have resulted in a series of compounds containing inexpensive amino acid residues but which produce broad spectrum BK receptor blocking potency and exceptional in vivo duration of action.