Department of Anesthesiology and Pain Medicine, Chonnam National University, Medical School, 8 Hakdong, Donggu, Gwangju 501-757, Republic of Korea.
Neurosci Lett. 2011 May 2;494(3):207-10. doi: 10.1016/j.neulet.2011.03.014. Epub 2011 Mar 21.
The authors examined the antinociceptive effect of melatonin in a nociceptive state and investigated a possible interaction with adrenergic or cholinergic receptors underlying this effect at the spinal level. Nociception was induced by a subcutaneous injection of 50 μl of a 5% formalin solution to the hindpaw of male Sprague-Dawley rats. The reversal effects of alpha-1 adrenoceptor antagonist (prazosin), alpha-2 adrenoceptor antagonist (yohimbine), muscarinic receptor antagonist (atropine) and nicotinic receptor antagonist (mecamylamine) on the activity of melatonin were assessed. Intrathecal melatonin reduced the flinching response during phase 1 and phase 2 in the formalin test. Intrathecal prazosin, yohimbine, atropine and mecamylamine increased the attenuating flinching response in both phases observed by intrathecal melatonin. Collectively, the present data suggest that intrathecal melatonin attenuates the facilitated state and acute pain evoked by formalin injection. Furthermore, the antinociception of melatonin is mediated through the alpha-1 adrenoceptor, alpha-2 adrenoceptor, muscarinic and nicotinic receptors in the spinal cord.
作者研究了褪黑素在疼痛状态下的镇痛作用，并在脊髓水平上研究了这种作用下与肾上腺素能或胆碱能受体的可能相互作用。通过向雄性 Sprague-Dawley 大鼠的后爪皮下注射 50μl 5%甲醛溶液来诱导疼痛。评估了α-1 肾上腺素能受体拮抗剂（哌唑嗪）、α-2 肾上腺素能受体拮抗剂（育亨宾）、毒蕈碱受体拮抗剂（阿托品）和烟碱受体拮抗剂（美加明）对褪黑素活性的逆转作用。鞘内注射褪黑素可减少福尔马林试验第 1 相和第 2 相的畏缩反应。鞘内注射哌唑嗪、育亨宾、阿托品和美加明均可增加鞘内褪黑素观察到的两相间的畏缩反应的衰减。总的来说，这些数据表明鞘内褪黑素可减轻福尔马林注射引起的易化状态和急性疼痛。此外，褪黑素的镇痛作用是通过脊髓中的α-1 肾上腺素能受体、α-2 肾上腺素能受体、毒蕈碱和烟碱受体介导的。
