A series of pseudopeptides containing alkyl-, cycloalkyl-, aryl-, and aralkyl-substituted 1, 3, 8- triazaspiro [4.5] decan-4-one-3-acetic acids as amino acid surrogates to replace the Pro2- Pro3-Gly4-Phe5 section of the peptide bradykinin B2 receptor antagonist [Pro3, Phe5] HOE 140 (d-Arg0-Arg 1-Pro 2-Pro 3-Gly 4-Phe 5-Ser 6-d-Tic 7-Oic 8-Arg 9) were prepared. These psuedopeptides were examined in vitro for their B2 receptor affinities as well as for their ...