RT - Journal Article T1 - Contribution of the Nucleus Cuneiformis to the Antinociceptive Effects of Systemic Morphine on Inflammatory Pain in Rats JF - BCN YR - 2011 JO - BCN VO - 3 IS - 1 UR - http://bcn.iums.ac.ir/article-1-197-en.html SP - 35 EP - 43 K1 - Nucleus Cuneiformis K1 - Electrolytic Lesion K1 - Reversible Inactivation K1 - Morphine K1 - Formalin Test K1 - Rat. AB - Introduction: The role of midbrain reticular formation, which includes the nucleus cuneiformis (NCF), as a crucial antinociceptive region in descending pain modulation has long been investigated. In this study, we tried to highlight the role of NCF in morphine-induced antinociception in formalin-induced pain model in rats. Methods: A total of 201 male Wistar rats weighing 260-310 g were used in this study. The effective dose of morphine in systemic administration (intraperitoneal i.p.) was determined after a dose- and time-response protocol. In consequent groups, bilateral electrolytic lesion (500 μA, 30 sec) or reversible inactivation (lidocaine 2%) were used in the NCF before systemic administration of morphine, and then, the nociceptive test was immediately carried out. Results: The results showed that administration of 6 mg/kg morphine, 30 min before the formalin test, is the best dose- and time-response set in these experiments. The obtained data also indicated that bilateral electrical destruction or reversible inactivation of the NCF significantly decreased antinociceptive responses of systemic morphine (6 mg/kg i.p.) during the second phase of formalin test (P LA eng UL http://bcn.iums.ac.ir/article-1-197-en.html M3 ER -