腺苷A2A受体拮抗剂对左旋多巴诱发异动症大鼠行为、纹状体A2A受体和代谢型谷氨酸受体5亚型蛋白表达的影响

目的 评价腺苷A2A受体拮抗剂(CSC)对左旋多巴(L-DOPA)诱发异动症大鼠行为、纹状体A2A受体和代谢型谷氨酸受体5亚型(mGluR5)蛋白表达的影响.方法 6-羟多巴胺(6-OHDA)立体定向损毁大鼠右内侧前脑束,建立单侧损毁帕金森病(PD)大鼠模型.采用随机数字表法将40只成功PD大鼠随机分为4组(每组10只):生理盐水组;L-DOPA 25 mg/kg+苄丝肼6.25 mg/kg组;CSC 2.5 mg/kg组;L-DOPA 25 mg/kg+苄丝肼6.25 mg/kg联合CSC 2.5 mg/kg组.给予大鼠每日2次腹腔注射,持续21 d.在治疗第2、9、11、18、21天观察大鼠行为学变化,Western blot检测纹状体区腺苷A2A受体和mGluR5的蛋白表达水平.结果 L-DOPA联合CSC组PD大鼠损毁对侧前肢跨步数显著增加,与治疗前比较差异有统计学意义,与L-DOPA组相比,前肢功能改善程度不随时间延长而减弱.单独CSC组治疗后对侧前肢跨步数明显增加,与治疗前比较差异有统计学意义,有疗效逐渐增加至稳定趋势.L-DOPA联合CSC组(11±5)分]部分口颌及肢体异常不自主运动评分较L-DOPA组(17±4)分]显著减少,差异有统计学意义(t=2.44,P＜0.05).L-DOPA联合CSC治疗逆转了L-DOPA诱导的对侧旋转反应时间缩短和腺苷A2A受体、mGluR5蛋白表达的上调,差异均有统计学意义.结论 腺苷A2A受体与mGluR5均参与了L-DOPA诱发的异动症的发生发展,A2A受体拮抗剂能够改善PD运动症状,增强L-DOPA的抗PD效应且部分减轻异常不自主运动,对L-DOPA诱发的异动症的治疗有着较好的应用前景.

Abstract：

Objective To study the behavioural changes and biological effects of selective adenosine A2A receptor antagonist (CSC) in a rat model of levodopa(L-DOPA) -induced dyskinesia (LID).Methods The hemi-parkinsonian rat model was produced by stereotaxically injecting 6-OHDA to the right medial forebrain bundle. Rats were randomly divided into 4 treatment groups with a random number generating program to receive intraperitoneal injections twice daily for 21 days (n = 10): saline, L-DOPA at 25 mg/kg with benserazide at 6. 25 mg/kg, CSC at 2. 5 mg/kg alone and CSC at 2.5 mg/kg with L-DOPA at 25 mg/kg plus benserazide at 6. 25 mg/kg. Forepaw adjusting steps, abnormal involuntary movements (AIM) and rotational response duration were observed on 2, 9, 11,18 and 21 d. After sacrifice, the expression of adenosine A2A R and mGluR5 was observed by Western blot. Results Co-administration of LDOPA with CSC significantly increased the forelimb adjusting steps of parkinsonian rats during 21 days of treatment when compared to L-DOPA alone. CSC treatment alone increased the forelimb adjusting steps significantly. Co-administration of L-DOPA with CSC ( ( 11 ± 5 ) score) significantly decreased the AIM scores of limb and orolingual muscles when compared to L-DOPA alone (( 17 ± 4) score; t = 2. 44, P ＜0. 05). The subchronic L-DOPA treatment upregulated the striatal expression of adenosine A2A R and mGluR5. However, co-administration of L-DOPA with CSC reversed the shortening of the rotational motor response duration induced by L-DOPA administration during the period of the treatment and attenuated the LDOPA-induced upregulation of adenosine A2A R and mGluR5 expressions. Conclusions CSC improves motor function in a hemi-parkinson rat model, potentiates the antiparkinsonian effects with L-DOPA and partly attenuates LID. Co-administration of L-DOPA with CSC reverses the L-DOPA-induced upregulated expression of A2A R and mGluR5, indicating the involvement of both A2A R and mGluR5 in the onset and progression of LID. Adenosine A2AR antagonists may be promising drugs for treatment of LID.

The effects of adenosine A2A receptor antagonist on the behavior and the striatal A2A receptor,metabotropic glutamate receptors protein expression in rats with levodopa-induced dyskinesia

Objective To study the behavioural changes and biological effects of selective adenosine A2A receptor antagonist (CSC) in a rat model of levodopa(L-DOPA) -induced dyskinesia (LID).Methods The hemi-parkinsonian rat model was produced by stereotaxically injecting 6-OHDA to the right medial forebrain bundle. Rats were randomly divided into 4 treatment groups with a random number generating program to receive intraperitoneal injections twice daily for 21 days (n = 10): saline, L-DOPA at 25 mg/kg with benserazide at 6. 25 mg/kg, CSC at 2. 5 mg/kg alone and CSC at 2.5 mg/kg with L-DOPA at 25 mg/kg plus benserazide at 6. 25 mg/kg. Forepaw adjusting steps, abnormal involuntary movements (AIM) and rotational response duration were observed on 2, 9, 11,18 and 21 d. After sacrifice, the expression of adenosine A2A R and mGluR5 was observed by Western blot. Results Co-administration of LDOPA with CSC significantly increased the forelimb adjusting steps of parkinsonian rats during 21 days of treatment when compared to L-DOPA alone. CSC treatment alone increased the forelimb adjusting steps significantly. Co-administration of L-DOPA with CSC ( ( 11 ± 5 ) score) significantly decreased the AIM scores of limb and orolingual muscles when compared to L-DOPA alone (( 17 ± 4) score; t = 2. 44, P ＜0. 05). The subchronic L-DOPA treatment upregulated the striatal expression of adenosine A2A R and mGluR5. However, co-administration of L-DOPA with CSC reversed the shortening of the rotational motor response duration induced by L-DOPA administration during the period of the treatment and attenuated the LDOPA-induced upregulation of adenosine A2A R and mGluR5 expressions. Conclusions CSC improves motor function in a hemi-parkinson rat model, potentiates the antiparkinsonian effects with L-DOPA and partly attenuates LID. Co-administration of L-DOPA with CSC reverses the L-DOPA-induced upregulated expression of A2A R and mGluR5, indicating the involvement of both A2A R and mGluR5 in the onset and progression of LID. Adenosine A2AR antagonists may be promising drugs for treatment of LID.