Role of neurotransmitters, such as PACAP and nociceptin, on the nociceptive transmission in the rat spinal cord.

电生理研究：利用离体新生大鼠脊髓标本，研究脊髓PAC1受体在伤害性信息传递中的作用。作为一种PAC1受体激动剂，将maxadilan应用于脊髓，可导致持续时间较长的腹侧神经根去极化，且呈剂量依赖性。Max.d的一个应用。PAC1受体拮抗剂4对脊髓产生抑制作用，对脊髓背根诱发的慢腹侧根电位（slow ventral root potential，慢VRP）呈剂量依赖性。这些结果提示，大鼠新生脊髓中PAC1受体在伤害性信息传递中起重要作用。行为学和免疫组化研究考察了阿片受体样1 （ORL1）受体在脊髓损伤性传递和fos样免疫反应性表达中的作用。鞘内注射ORL1受体激动剂nociceptin可抑制足部福尔马林诱导的L5大鼠脊髓I-II层fos样免疫反应性的表达。在神经性疼痛模型的研究中，预先给药痛觉肽可延缓坐骨神经慢性收缩损伤而非部分坐骨神经损伤引起的热痛觉过敏的发生；可抑制坐骨神经慢性收缩损伤而非部分坐骨神经损伤引起的fos样免疫反应的表达。这些数据表明，脊髓ORL1受体的激活抑制了大鼠脊髓中的伤害性传递。

Electrophysiological study:I studied the role of spinal PAC1 receptor on the nociceptive information transmission using an isolated neonatal rat spinal cord preparation. Application of maxadilan to the spinal cord, a PAC1 receptor agonist, resulted in a long lasting ventral root depolarizaion in a dose dependent manner. An application of Max.d.4, a PAC1 receptor antagonist, to the spinal cord produced the depressant effect on the dorsal root evoked slow ventral root potential (slow VRP) in a dose dependent manner. These results suggested that PAC1 receptor in the rat neonatal spinal cord plays an important role in the nociceptive information transmission.Behavioral and Immunohistochemical StudyI examined the role of the opioid receptor like 1 (ORL1) receptor on the nociceptive transmission and thfe expression of Fos-like immunoreactivity of the spinal cord. Intrathecal injection of nociceptin, an ORL1 receptor agonist, depressed the agitation behavior induced by paw formalin injection and inhibited the expression of Fos-like immunoreactivity in the laminae I-II of L5 rat spinal cord. In the study of neuropathic pain model, pre-emptively administered nociceptin delayed the development of thermal hyperalgesia induced by the chronic constriction injury of the sciatic nerve, but not by the partial sciatic nerve injury and depressed the expression of Fos-like immunoreactivity induced by the chronic constriction injury of the sciatic nerve, but not by the partial sciatic nerve injury. These data suggested that activation of spinal ORL1 receptor suppressed the nociceptive transmission in the rat spinal cord.