Intrathecal bradykinin administration: opposite effects on nociceptive transmission.

Injected intrathecally, bradykinin (BK) produced either hyperalgesia (0.15 microg) or antinociception (6.0 microg) in rats when thermal noxious stimuli were used.

Inhibition of inducible nitric oxide synthase in persistent pain.

The present study was undertaken to investigate the role of inducible nitric oxide synthase in a rat model of persistent pain. The effects of L-N6 (1-iminoethyl) lysine (L-NIL), a relatively potent and relatively selective inhibitor of inducible nitric oxide synthase, were investigated in carrageenan induced hyperalgesia L-NIL (0.1 microMole) injected intraplantar or intrathecal markedly enhanced carrageenan induced hyperalgesia.

Spinal co-administration of peptide substance P antagonist increases antinociceptive effect of the opioid peptide biphalin.

Intrathecal injection of 0.25 micrograms of undecapeptide substance P antagonist (SPA) produced transient antinociception with a peak effect at 5 min. Increasing the SPA dose resulted in neurotoxicity.

Synthesis of enkephalin analogs. Part VI. N,N-disubstituted derivatives.

Synthesis of four new N,N-disubstituted derivatives of enkephalin analogs: All2Tyr-DMet-Gly-Phe-epsilon Ahx-OMe 5, Bu2Tyr-DMet-Gly-Phe-epsilon Ahx-OMe 6, All2Tyr-DMet-Gly-Phe-epsilon Ahx-epsilon Ahx-OMe 11 and Bu2Tyr-DMet-Gly-Phe-epsilon Ahx-epsilon Ahx-OMe 12 is reported. they were tested for agonistic and antagonistic activity. Compound 5 is a little more potent agonist (IC50 = 1.

Synthesis of enkephalin analogs. Part V. N-monosubstituted derivatives.

Synthesis of four new derivatives of enkephalin analogs: H-BuTyr-DMet-Gly- Phe-epsilon Ahx-OH 9, H-BzlTyr-DMet-Gly-Phe-epsilon Ahx-OH 12, H-Butyr-DMet-Gly- -Phe-epsilon Ahx-epsilon Ahx-OH 15 and H-BzlTyr-DMet-Gly-Phe-epsilon Ahx-OH is reported. They were examined for agonistic, antagonistic and analgesic activity. Compound 12 is the most potent among investigated peptides.