吗啡精神依赖大鼠VTA-NAc-PFC神经环路谷氨酸含量和NR2B表达的变化

目的 观察吗啡诱导条件性位置偏爱大鼠中脑腹侧被盖区-伏核-前额叶皮质(VTA-NAc-PFC)神经环路各核团谷氨酸递质含量和N-甲基-D-天冬氨酸受体亚基NR2B表达的变化,从受体前和受体层面探讨该环路中通过谷氨酸能系统的阿片类精神依赖机制.方法 筛选出合格大鼠32只并按随机数字表法分为生理盐水对照组和吗啡条件性位置偏爱模型组(模型组),模型组采用吗啡剂量递增法建立大鼠条件性位置偏爱模型,分别用比色法和免疫组化染色检测中脑腹侧被盖区、伏核和前额叶皮质内谷氨酸含量和NR2B的表达.结果 与生理盐水对照组比较,模型组大鼠在白箱的停留时间明显延长,VTA-NAc-PFC神经环路各核团谷氨酸含量明显增高,NR2B平均吸光度值明显增加,差异均有统计学意义(P<0.05).结论 VTA-NAc-PFC神经环路谷氨酸递质含量及其受体亚基NR2B表达水平上调在吗啡精神依赖形成中发挥重要作用.

Abstract：

Objective To explore the mechanism of opioid-psychic dependence involving the aspects of pre-receptor and receptor by observing the changeable expressions of glutamate neurotransmitter and NR2B of N-methyl-D-aspartic acid (NMDA) receptor in the neuroanatomical circuit of ventral temental area, nucleus accumbens and prefrontal cortex (VTA-Nac-PFC) of rats subjected to morphine-induced conditioned place preference (CPP). Methods The models of CPP were validated by escalating doses of morphine in rats (n=16). The colorimetry and immunohistochemistry ways were applied to detect the contents of glutamic acid and the expression level of NR2B in VTA, Nac and PFC. Results As compared with those in the control group physiological saline), the prolonged detention time of white compartment in the model group was notably observed (P<0.05), and increased content of glutamic acid and expression level of NR2B in fields of VTA, Nac and PFC in the model group were significantly detected (P<0.05). Conclusion Increased level of giutamic acid and expression level of NR2B in nuroanatomieal circuit of VTA, Nac and PFC could play key roles in inducing morphine-psychic dependent rats.

Changeable expressions of glutamate neurotransmitter and NR2B in neuroanatomical circuit of ventral temental area, nucleus accumbens and prefrontal cortex in morphine-psychic dependent rats

Objective To explore the mechanism of opioid-psychic dependence involving the aspects of pre-receptor and receptor by observing the changeable expressions of glutamate neurotransmitter and NR2B of N-methyl-D-aspartic acid (NMDA) receptor in the neuroanatomical circuit of ventral temental area, nucleus accumbens and prefrontal cortex (VTA-Nac-PFC) of rats subjected to morphine-induced conditioned place preference (CPP). Methods The models of CPP were validated by escalating doses of morphine in rats (n=16). The colorimetry and immunohistochemistry ways were applied to detect the contents of glutamic acid and the expression level of NR2B in VTA, Nac and PFC. Results As compared with those in the control group physiological saline), the prolonged detention time of white compartment in the model group was notably observed (P<0.05), and increased content of glutamic acid and expression level of NR2B in fields of VTA, Nac and PFC in the model group were significantly detected (P<0.05). Conclusion Increased level of giutamic acid and expression level of NR2B in nuroanatomieal circuit of VTA, Nac and PFC could play key roles in inducing morphine-psychic dependent rats.