纹状体多巴胺D_2受体对大鼠皮层-苍白球异常同步振荡活动的调节作用

The regulation effect of striatal dopamine D_2 receptors involved in the rat's cortex-globus pallidus abnormal synchronous oscillation activity

目的探讨多巴胺受体对成年大鼠自由活动状态下的皮层-苍白球异常同步振荡活动的调节作用。方法利用微量给药系统向纹状体注射不同的多巴胺受体拮抗剂,通过在体多通道电生理记录结合视频录像,观察大鼠皮层、苍白球HVSs节律个数、持续时间,分析皮层、苍白球HVSs节律的相对功率谱,以及计算皮层-苍白球之间的相干系数。结果与对照组相比,纹状体微量注射多巴胺D2受体拮抗剂组,HVSs节律个数增多、持续时间延长,功率谱分析显示皮层、苍白球HVSs节律相对功率增加,相干分析显示皮层-苍白球之间同步性显著增高,而注射多巴胺D1受体拮抗剂组HVSs节律无明显改变。结论帕金森病状态下大鼠皮层、苍白球出现异常HVSs节律,纹状体多巴胺D2受体而非D1受体参与HVSs节律的调节,提示"间接通路"在皮层-苍白球异常同步振荡活动中起重要作用。

Objective To study the effect of striatal dopamine D2 receptors in regulation of rat＇s cortex -- globus pallidus abnormal synchronous oscillation activity. Methods Continuous video,neocortical electroencephalogram （EEG） and local field potential （LFP） of globus pallidus （GP） were recorded simultaneously in freely moving rats. The number and duration of high--voltage spindles （HVSs） were analyzed after striatal microinjection of dopamine receptor antagonists （SCH23390,raclopride） or saline. Power spectral densities （PSD） and coherence analysis were used to analyze frequency components of signals and synchronization between M1 cortex and GP,respectively. Results Compared with saline group, the number of HVSs increased and the mean duration of HVSs were prolonged significantly in raclopride group as well as the relative power of HVSs in M1 and GP were increased. Coherence analysis showed that the HVSs synchronization between M1 and GP was increased significantly too. In contrast, there were no significant changes in SCH23390 group. Conclusion The HVSs in Parkinson＇s disease are abnormal and may be associated with hypokinesia in the parkinsonian condition. The dopamine D2 but not D1 receptors are involved in the regulation of HVSs indicating that the ＂indirect＂ pathway striatal neurons may contribute to the regulation of cortical--GP synchronous oscillation.