Zhou W, Liu H, Xie X
Ningbo Institute of Microcirculation & Henbane, Ningbo Drug Addiction Research and Treatment Center, Ningbo 315010, China.
Zhonghua Yi Xue Za Zhi. 2000 Feb;80(2):135-9.
To investigate the expression of glial cell derived neurotrophic factor (GDNF) and its receptor GDNFR-alpha (GFRalpha-1) and GDNFR-beta (Ret) genes and the effects of muscarinic receptor antagonists, NMDA receptor antagonist, inhibitor of nitric oxide synthase on the expression of these genes in the spinal cord, brainstem and frontal cortex during morphine withdrawal, and to observe the effects of GDNF antisense oligoneucleotide (i.c.v) on the morphine withdrawal symptoms in rats.
The levels of GDNF, GDNFR-alpha and GDNFR-beta mRNA were assayed by reverse transcription polymerase chain reaction (RT-PCR) with the beta-actin mRNA as an internal control.
The GDNF mRNA levels were increased, and GDNFR-alpha and GDNFR-beta mRNA levels was slightly increased in the spinal cord and brainstem during morphine dependence. These genes were decreased at 1 h, increased at 2 h after administration of naloxone in morphine dependent rats. While the GDNF, GDNFR-alpha and GDNFR-beta levels in the frontal cortex were increased significantly at 1, 2 and 4 h after the injection of naloxone during morphine withdrawal. The pre-treatment with L-N-nitric arginine methylester (10 mg/kg), the expressions of GDNF and GDNFR-beta in the spinal cord, both GDNFR-alpha and GDNFR-beta in the frontal cortex were decreased. The expressions of both GDNF and GDNFR-alpha in the frontal cortex were decreased by treatment with MK801 (0.5 mg/kg), and the expressions of GDNF in both the stem and cortex, and GDNFR-beta in the brainstem decreased by treatment with the methyl-scopolamine (0.5 mg/kg). The beta-actin mRNA levels were not different in each group. Moreover, the morphine withdrawal symptoms were attenuated by intracerebroven tricular injection of GDNF antisense oligoneucleotide in 6 hour and 24 hour before naloxone administration in morphine dependent rats.
The results not only provide direct evidence that the expressions of GDNF and its receptors mRNA in glial cells play an important role in mediating the process of morphine dependence and may be account for the long-term neuro-adaptation associated with morphine dependence, but also suggest that muscarinic receptor, NMDA receptor and nitric oxide pathways may be involved in the expression of GDNF and GDNF receptor genes during morphine withdrawal.
研究胶质细胞源性神经营养因子（GDNF）及其受体GDNFR-α（GFRα-1）和GDNFR-β（Ret）基因的表达，以及毒蕈碱受体拮抗剂、NMDA受体拮抗剂、一氧化氮合酶抑制剂对吗啡戒断期间脊髓、脑干和额叶皮质中这些基因表达的影响，并观察GDNF反义寡核苷酸（脑室内注射）对大鼠吗啡戒断症状的影响。
以β-肌动蛋白mRNA为内对照，采用逆转录聚合酶链反应（RT-PCR）检测GDNF、GDNFR-α和GDNFR-β mRNA水平。
吗啡依赖期间，脊髓和脑干中GDNF mRNA水平升高，GDNFR-α和GDNFR-β mRNA水平略有升高。在吗啡依赖大鼠中，注射纳洛酮后1小时这些基因水平降低，2小时升高。而在吗啡戒断期间，注射纳洛酮后1、2和4小时，额叶皮质中GDNF、GDNFR-α和GDNFR-β水平显著升高。用L-N-硝基精氨酸甲酯（10 mg/kg）预处理后，脊髓中GDNF和GDNFR-β的表达以及额叶皮质中GDNFR-α和GDNFR-β的表达均降低。用MK801（0.5 mg/kg）处理后，额叶皮质中GDNF和GDNFR-α的表达均降低，用甲基东莨菪碱（0.5 mg/kg）处理后，脑干和皮质中GDNF的表达以及脑干中GDNFR-β的表达均降低。各组β-肌动蛋白mRNA水平无差异。此外，在吗啡依赖大鼠中，在注射纳洛酮前6小时和24小时脑室内注射GDNF反义寡核苷酸可减轻吗啡戒断症状。
这些结果不仅提供了直接证据，表明胶质细胞中GDNF及其受体mRNA的表达在介导吗啡依赖过程中起重要作用，可能是与吗啡依赖相关的长期神经适应性的原因，还表明毒蕈碱受体、NMDA受体和一氧化氮途径可能参与吗啡戒断期间GDNF和GDNF受体基因的表达。
