Antiopioid properties of the TYR-MIF-1 family.

The Tyr-MIF-1 family of peptides includes MIF-1, Tyr-MIF-1, Tyr-W-MIF-1 and Tyr-K-MIF-1, which have been isolated from bovine hypothalamus and human brain cortex. All these peptides interact with opioid receptors and in addition bind to non-opiate sites specific for each of the peptides. Data in the literature suggest that peptides of the Tyr-MIF-1 family (Tyr-MIF-1s) have antiopioid and opioid- like effects.

Effects of Tyr-MIF's family of peptides on immobilization stress-induced antinociception in rats.

Unlabelled: The Tyr-MIF-1 family of peptides includes MIF-1, Tyr-MIF-1, Tyr-W-MIF-1 and Tyr-K-MIF-1, which have been isolated from bovine hypothalamus and cortex of human brain. Data in the literature suggest that peptides of Tyr-MIF-1's family have opioid-like and anti-opioid actions. All these peptides interact with opioid receptors and in addition bind to non-opiate sites specific for each of the peptides and able to inhibit the expression of some forms of stress-induced analgesia (SIA) in various species.

Effects of kyotorphin and analogues on nociception and pentylenetetrazole seizures.

Unlabelled: Kyotorphin (Kyo) is synthesized in specific brain regions where it may modulate synaptic transmission and directly excites cortical neurons, and indirectly exerts opioid actions to produce analgesia via release of met-enkephalin. Kyo is formed by specific enzyme from L-tyrosine and L-arginine in the presence of ATP and Mg2+ in the brain. Kyo and its analogues Tyr-Cav, Tyr (Cl2)-Cav exerted naloxone-reversible antinociception by paw-pressure test.