The analgesic activity of some kyotorphin-tuftsin analogs.

: The analgesic potency of the C-terminal dipeptide of tuftsin (Pro-Arg) was found to be much stronger than that of the C-terminal of bradykinin dipeptide Phe-Arg. It was also found that the tripeptide fragment of bradykinin (Pro-Phe-Arg) and its D-Pro analog (D-Pro-Phe-Arg) are deprived of analgesic activity. The attempt to synthesize kyotorphin analogs containing fluorescence label (DMAPhe-Arg and D-DMAPhe-Arg; DMAPhe: 4'-dimethylamino-phenylalanine) resulted in inactive compounds.