Bradykinin (BK), kallidin (KD), and various analogues induced histamin
e release from rat mast cells. The results obtained with substituted a
nalogues of BK indicated that: 1) the presence of both Arg residues at
position 1 and 9 of kinins was favorable to confer histamine-releasin
g activity, 2) acetylation of the N-terminal amino acid residue led to
a drastic reduction of this activity, 3) addition of a D-Arg residue
at the N-terminus reduced their activity, as well as trans-4-hydroxypr
oline (Hyp) substitutions at position 2 or 3, 4) D-Arg0 addition and H
yp3 substitution were synergistic in lowering activity, and 5) D-Phe7
substitution led to enhanced histamine-releasing activity.