Prolonged analgesia after intracerebroventricular Tyr-W-MIF-1 (Tyr-Pro-Trp-Gly-NH2).
A peptide recently isolated from human and bovine brain, Tyr-W-MIF-1 (Tyr-Pro-Trp-Gly-NH2), was tested for its effects on nociception in the tail-flick test after intracerebroventricular injection in the rat. Tail-flick latencies were significantly increased with a rapid onset and remained significantly elevated for at least 50 min. Naloxone reversed the effect of the peptide, indicating opiate receptor involvement in the response. Met-enkephalin at the same dose produced only slight antinociception. Some animals showed 'barrel-rolling' behavior in addition to the analgesia; this behavior was unusually short-lived, not a prerequisite for the analgesia, and had no apparent persistent effects. The results show that, in addition to previously described opiate-like actions (binding to the mu-receptor and inhibition of electrically induced contractions of the guinea pig ileum), Tyr-W-MIF-1 is capable of inducing significant analgesia.
Zadina
J E
JE
Veterans Affairs Medical Center, New Orleans, LA 70146.
Kastin
A J
AJ
Kenigs
V
V
Bruno
C
C
Hackler
L
L
D000595:Amino Acid Sequence; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D007276:Injections, Intraventricular; D009075:MSH Release-Inhibiting Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008297:Male; D008969:Molecular Sequence Data; D009043:Motor Activity / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D010146:Pain / Q000517:prevention & control; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000701:Analgesics, Opioid; C077532:tyrosyl-prolyl-tryptophyl-glycinamide; D009270:Naloxone; D009075:MSH Release-Inhibiting Hormone