Effects of Tyr-MIF-1 on stress-induced analgesia and the blockade of development of morphine tolerance by stress in mice.
The role of Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) in biological responses to stress exposure was examined in mice. Intraperitoneal or intracerebroventricular administration of Tyr-MIF-1 attenuated not only footshock (FS)- and forced swimming (SW)-stress-induced analgesia (SIA) but also socio-psychological (PSY)-SIA that, when using the communication box, is produced without any direct physical nociceptions. Tyr-MIF-1 also disrupted the suppressive effect of concurrent exposure to FS- and PSY-stress on the development of morphine antinociceptive tolerance. In elevated-plus-maze tests, mice treated with Tyr-MIF-1 tended to spend more time in the open arms compared with the control group, suggesting the anxiolytic properties of the peptide. Thus, the finding that Tyr-MIF-1 modulates these stress responses suggests that the peptide regulates an endogenous biological alert system responding to stress exposure, perhaps, counteracting the excessive response of the system. Furthermore, Tyr-MIF-1, in the case of PSY-stress, through the attenuation of emotional factors such as fear and anxiety, may suppress PSY-SIA and inhibition by PSY-stress of the development of morphine tolerance.
Fukunaga
H
H
Department of Pharmacoinformatics, School of Pharmaceutical Sciences, Nagasaki University, Japan.
Takahashi
M
M
Kaneto
H
H
Yoshikawa
M
M
D000701:Analgesics, Opioid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D004347:Drug Interactions; D004361:Drug Tolerance / Q000502:physiology*; D009075:MSH Release-Inhibiting Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D010146:Pain; D010147:Pain Measurement / Q000379:methods; D013312:Stress, Physiological / Q000503:physiopathology*; D013550:Swimming
D000701:Analgesics, Opioid; D014151:Anti-Anxiety Agents; D009020:Morphine; C036930:tyrosyl-prolyl-leucyl-glycinamide; D009075:MSH Release-Inhibiting Hormone