Hu W H, Qiang W A, Li F, Liu N, Wang G Q, Wang H Y, Wan X S, Liao W H, Liu J S, Jen M F
Department of Spinal Cord Injury, Research Institute of Surgery and Daping Hospital, The Third Military Medical University, Chongqing, People's Republic of China.
J Chem Neuroanat. 2000 Jan;17(4):183-97. doi: 10.1016/s0891-0618(99)00039-3.
It has recently been demonstrated that selective inhibition of both neuronal constitutive and inducible nitric oxide synthases (ncNOS and iNOS) is neuroprotective in a model of dynorphin (Dyn) A(1-17)-induced spinal cord injury. In the present study, various methods including the conversion of 3H-L-arginine to 3H-citrulline, immunohistochemistry and in situ hybridization are employed to determine the temporal profiles of the enzymatic activities, immunoreactivities, and mRNA expression for both ncNOS and iNOS after intrathecal injection of a neurotoxic dose (20 nmol) of Dyn A(1-17). The expression of ncNOS immunoreactivity and mRNA increased as early as 30 min after injection and persisted for 1-4 h. At 24-48 h, the number of ncNOS positive cells remained elevated while most neurons died. The cNOS enzymatic activity in the ventral spinal cord also significantly increased at 30 min 48 h, but no significant changes in the dorsal spinal cord were observed. However, iNOS mRNA expression increased later at 2 h, iNOS immunoreactivity and enzymatic activity increased later at 4 h and persisted for 24-48 h after injection of 20 nmol Dyn A(1-17). These results indicate that both ncNOS and iNOS are associated with Dyn-induced spinal cord injury, with ncNOS predominantly involved at an early stage and iNOS at a later stage.
最近有研究表明，在强啡肽（Dyn）A（1-17）诱导的脊髓损伤模型中，选择性抑制神经元组成型和诱导型一氧化氮合酶（ncNOS和iNOS）具有神经保护作用。在本研究中，采用了多种方法，包括将³H-L-精氨酸转化为³H-瓜氨酸、免疫组织化学和原位杂交，以确定鞘内注射神经毒性剂量（20 nmol）的Dyn A（1-17）后，ncNOS和iNOS的酶活性、免疫反应性和mRNA表达的时间变化情况。注射后30分钟，ncNOS免疫反应性和mRNA的表达就开始增加，并持续1至4小时。在24至48小时，ncNOS阳性细胞数量仍然升高，而大多数神经元已经死亡。脊髓腹侧的cNOS酶活性在30分钟至48小时也显著增加，但脊髓背侧未观察到明显变化。然而，iNOS mRNA表达在2小时后增加，iNOS免疫反应性和酶活性在4小时后增加，并在注射20 nmol Dyn A（1-17）后持续24至48小时。这些结果表明，ncNOS和iNOS都与Dyn诱导的脊髓损伤有关，ncNOS主要在早期起作用，而iNOS在后期起作用。
