Stress-induced opioid analgesia and activity in mice: inhibitory influences of exposure to magnetic fields.
An exposure for 30 min to a 0.5 Hz rotating magnetic field (1.5-90 G) significantly reduced immobilization stress-induced, opioid analgesia and hyperactivity in CF-1 and C-57 BL strains of mice, respectively. The magnetic exposure also eliminated the day-night rhythm in stress-induced analgesia, with maximum inhibitory effects occurring in the dark period. Pre-treatment with naloxone (1.0 mg/kg) had comparable inhibitory effects on immobilization-induced analgesia and activity. These results suggest that exposure to magnetic stimuli can significantly influence stress-induced activation of endogenous opioid systems and their behavioral and physiological consequences.
D000818:Animals; D001921:Brain / Q000503:physiopathology; D004723:Endorphins / Q000502:physiology*; D006358:Hot Temperature; D008280:Magnetics; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000503:physiopathology*
D004723:Endorphins