To study the effects of acute sucrose ingestion on threshold of pain in chronic extremely low frequency magnetic fields exposed rats and whether sucrose ingestion potentiates the analgesia of magnetic field exposure.
Both magnetic field exposure and sucrose ingestion can produce opioid mediated analgesia independently.
Male rats (n=6) were studied in four experimental conditions: 1) sham exposure (day 1-7), 2) control sucrose-ingestion (day 9), 3) magnetic field exposure (day 10-16), 4) magnetic field exposure + sucrose-ingestion (day 17). Nociceptive behavior was studied by 21 noxious electrical stimuli during 7 sessions (0, 5, 10, 15, 30, 45 and 60 min).
|Exposure duration||continuous for 8 h/day for 7 days|
Group 1) vs. 3): The basal threshold of pain (at 0 min) did not vary between the control group and the magnetic field exposed rats. During session 2 to 7, the pain thresholds did not vary in the control group but increased in exposed rats. The pain thresholds of exposed rats were elevated compared to the control group.
Group 2) vs. 4): Control sucrose group vs. magnetic field sucrose group elevated the threshold of tail response in control rats but not in the exposure group. The thresholds of vocalization during and after stimulus were more elevated in control rats than in exposed rats.
The results suggest that the magnetic field exposure for 7 days did not affect the basal thresholds of pain, but it increased stress (repeated presentation of noxious stimuli) induced analgesia. Ingestion of sucrose by the magnetic field exposed rats did not potentiate analgesia. It attenuated the stress induced analgesia. Opiod mediated behaviors may be compromised under chronic magnetic field exposure.