Abstract: (10095 Views)
Post-operative pain and its management remains one of the most important issues in the field of surgery and health care system. On the other hand, opioid drug abuse has a large prevalence in Iran. Formalin test has been used as a method for assessing pain and analgesia in rats. In the present study, the post-operative pain in morphine addicted rats was compared with that of non-addicted ones using formalin test. For this purpose, 26 rats were chosen and randomly divided into two groups. First group received morphine sulphate in their drinking water for 21 days. The other group received only tap water. On the day of their assessment, a longitudinal incision (1-cm) was made through skin fascia of their plantar aspect of one foot under ether anesthesia. One hour later, their pain was assessed with formalin test through intra-plantar subcutaneous injection of 0.05 ml of 2.5% formalin solution. Our results showed that acute pain (the first 5 minutes after injection) in both groups was not different significantly, but chronic pain (the next 15-45 minutes) was much intense in morphine-addicted rats.