可视法膜片钳术观察大鼠黑质-纹状体脑片中黑质细胞电生理特性

Electrophysiological characteristics of neurons in rat substantia nigra by visual patch clamp technique

目的建立大鼠黑质-纹状体脑片，探讨中脑黑质细胞的电生理特性。方法应用红外微分干涉相差（IR—DIC）技术在直视下对黑质-纹状体脑片中100个黑质细胞动作电位及超极化激活的内向电流（Ih）进行观察和分析。结果可视法脑片膜片钳术可对脑片中黑质细胞进行准确定位和功能状态的筛选。记录的100个细胞中94个可见自发动作电位，其中频率〈10Hz的85个（A类细胞），平均为（5．0±2．7）Hz；〉10Hz的9个（B类细胞），平均为（14．0±2．6）Hz。后者电位变化过程与前者相比缺少明显的超极化。92．9％（79／85）的A类细胞诱发出明显的Ih电流（-120mV，47．5pA±5．8pA），提示为多巴胺能细胞；B类细胞则没有或只有很小的Ih电流（-120mV，4．9pA±1．5pA），提示为γ-氨基丁酸能细胞。两者比较P〈0．001。结论通过在可视条件下对黑质-纹状体脑片黑质细胞进行基本电学特征观察，可有效地识别黑质细胞的类型，为深入研究黑质-纹状体通路电信号的发生和传递提供了基础。

Objective To establish the brain slices of substantia nigra and striatum in rats and study the properties and functional significance of substantia nigra neurons. Methods The technique of infrared differential interference contrast （IR-DIC） and CCD-Camera system with visual patch clamp whole-cell recording were combined. One hundred healthy substantia nigra neurons were located and the measurements of active potential and Ih current recorded and analyzed. Results Visual patch clamp technique could be used to make a direct localization of substantia nigra and to identify the active neurons. Spontaneous active potential was shown in 94/100 neurons. Among them, 85 （Group A） had a frequency less than 10Hz and 9 more than 10Hz （Group B）. The means were （5.0±2.7）Hz and （14.0 ±2.6）Hz. respectively. As compared with the former, the latter had no obvious hyperpolarization during active potential period. Apparent hyperpolarizing current could be induced in 92. 9% （79/85） of Group A neurons （ -120 mV, 47.5 pA ±5.8 pA）. They were classified as dopaminergic neurons. However, the Group B neurons had no or little Ih current and were classified as GABA neurons （ P 〈 0. 001 ）. Conclusion The types of nigra neurons can be distinguished by observing the fundamental electrical characteristic of dopaminergic neurons in nigrostriatal brain slices under visual inspections. And it may provide rationales for an in-depth knowledge of the occurrence and transmission of signal pathways between substantia nigra and striatum.