Razi Journal of Medical Sciences

Background: Many evidences have shown that aerobic exercise can alter the function and release certain neurotransmitters such as opioids in the brain. In this research, the effect of endurance exercise (running on a treadmill for six weeks) and oral magnesium sulphate on pain threshold of addicted rats following withdrawal syndrome was investigated.

Methods: In this study male wistar rats weighting 250±20g were used. Morphine sulphate 0.4 grams per liter was added to the animal’s water and after 21 days they were addicted to morphine. Endurance exercise training was used to train animals for six weeks. At the end of the second, fourth and sixth weeks of exercise protocol, naloxone hydrochloride were injected at a rate of 3 mg/kg. Magnesium sulphate 10 grams/liter was dissolved for six weeks in drinking water of animals that were taking magnesium sulphate. A tail-flick apparatus were used to evaluate the effect of exercise and magnesium sulphate on pain threshold.

Results: Results showed that treadmill running exercise (p<0.05) and intake of magnesium (p<0.01) caused a significant increase in pain threshold in addicted rats at withdrawal period. Also, the simultaneous effect of running exercise and intake of magnesium sulphate on pain threshold was greater than any component solely.

Conclusion: According to the findings of this study, it seems that the effect of exercise can be potentiated with magnesium sulphate and may be helpful to ease the pain at withdrawal period.