Tyr-MIF-1, identified in brain tissue, and its analogs are active in two models of antinociception.
The antiopiate activities of Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) and some of its representative analogs were tested in two animal models of antinociception. Doses of the tetrapeptides as low as 0.001 mg/kg injected peripherally could block the analgesic effects of morphine in both the tail-flick test of mild thermal pain induced by heat and the scratching test of mild chemical pain induced by hypertonic saline. These tetrapeptides showed cross-reactivity in the radio-immunoassay (RIA) used to identify the presence of Tyr-MIF-1 in brain extracts and in the brain membrane binding assay. Only Tyr-MIF-1, however, eluted at the position of the immunoreactive peak after gel filtration chromatography and high performance liquid chromatography (HPLC). The results support the concept that peptides with anti-opiate activity can exist in the brain.
Kastin
A J
AJ
Stephens
E
E
Zadina
J E
JE
Coy
D H
DH
Fischman
A J
AJ
D000701:Analgesics, Opioid / Q000037:antagonists & inhibitors*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001923:Brain Chemistry; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D009075:MSH Release-Inhibiting Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D051379:Mice; D009020:Morphine / Q000037:antagonists & inhibitors; D010146:Pain / Q000503:physiopathology; D011930:Reaction Time / Q000187:drug effects; D013329:Structure-Activity Relationship
D000701:Analgesics, Opioid; D009020:Morphine; C036930:tyrosyl-prolyl-leucyl-glycinamide; D009075:MSH Release-Inhibiting Hormone