延胡索及L-THP对吗啡条件性位置偏爱大鼠奖赏环路多巴胺系统的影响及比较

目的: 研究延胡索及左旋延胡索乙素(L-THP)对吗啡条件性位置偏爱(CPP)模型大鼠奖赏环路各脑区多巴胺递质与D2受体的影响及比较。 方法: 吗啡剂量递增颈背部皮下注射CPP训练10 d(起始剂量10 mg·kg^-1,每天递增10 mg·kg^-1,至注射10 d时为100 mg·kg^-1),末次训练后48 h CPP检测确认模型建立成功,即日(12 d)延胡索水提液2,1,0.5 g·kg^-1(分别含L-THP 0.153,0.077,0.038 mg),以及L-THP 3.76,1.88,0.94 mg·kg^-1灌胃治疗,共6 d,第18天再次CPP检测,次日取材用高效液相法测定其中脑腹侧被盖区-伏核-前额叶皮质(VTA-NAc-PFC)奖赏神经环路各脑区多巴胺递质含量,免疫组化和Western blotting检测D2受体的表达。 结果: 与生理盐水治疗组比较,延胡索2,1 g·kg^-1,以及L-THP 3.76,1.88 mg·kg^-1组大鼠在白箱(吗啡伴药箱)停留时间明显减少(P<0.01或P<0.05),同时VTA,NAc和PFC内多巴胺含量降低,D2受体表达显著增加(P<0.01或P<0.05)。 结论: 下调奖赏神经环路中升高的多巴胺含量和上调D2受体的表达,可能是延胡索与L-THP加速吗啡CPP效应消退的机制之一;对于抑制吗啡CPP效应以及对多巴胺系统的影响,含1倍量L-THP单体的延胡索中药相当于单独应用约24倍L-THP单体的效果。

Study on effects of Corydalis yanhusuo and L-THP on dopamine of reward circuitry in conditioned place preference rats and comparison

Objective: To study and compare the effect of Corydalis yanhusuo and L-THP on dopamine neurotransmitter and D2 receptor of reward circuitry in various cerebral areas of conditioned place preference model rats and the comparison of their effects. Method: The CPP model was established by injecting morphine in rats with increasing doses for 10 days. The initial dose of 10 mg·kg^-1, and the final dose of 100 mg·kg^-1, with 10 mg·kg^-1increased each day. At 48 h after the final training, CPP was adopted to detect the successful establishment of the model. On the same day (12 d), they were orally administered with 2, 1, 0.5 g·kg^-1 C. yanhusuo (containing 0.153, 0.077 and 0.038 mg L-THP) and L-THP (3.76, 1.88, 0.94 mg·kg^-1) for six days. On 18 d, CPP test was performed again. Next day, HPLC was adopted to determine the content of dopamine neurotransmitters of reward circuitry in VTA-NAc-PFC;Immunohistochemistry and Western blotting were adopted to detect the expression of D2 receptors. Result: Compared with the physiological saline treatment group, C. yanhusuo (2, 1 g·kg^-1) and L-THP (3.76, 1.88 mg·kg^-1) groups showed that rats stayed in a notably shorter period in white boxes (morphine-accompanied boxes) (P<0.01 or P<0.05), and revealed a remarkably lower dopamine content in VTA, NAc and PFC and the significant increase in the expression of D2 receptor (P<0.01 or P<0.05). Conclusion: The down-regulation of the increased dopamine content in reward nervous circuitry and the up-regulation of the expression of D2 receptor may be one of mechanisms of C. yanhusuo and L-THP in accelerating the recession of morphine's CPP effect. Regarding the inhibition of morphine's CPP effect and the effect on dopamine system, the effect of C. yanhusuo traditional Chinese medicine containing one-fold L-THP monomer is equal to that of the independent application of around 24-fold L-THP monomer.