Kong Yan, Xu Zhuan, Dong Wan-li, Cai Xiu-ying, Duan Xiao-yu, Cao Bi-yin
Department of Neurology, First Affiliated Hospital, Soochow University, Suzhou 215006, China.
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Zhonghua Yi Xue Za Zhi. 2013 Nov 19;93(43):3470-4.
To explore the effects of endogenous dopamine (DA) on striatum medium spiny neurons (MSNs) in acute brain slices by the means of electrophysiology and elucidate the impact of nigrostriatal circuit loop on the functional status of MSNs.
Various structural combinations of striatum and cortex or/and substantia nigra were used to explore the conditions with appearance of spontaneous two-state voltage oscillations. And the blockage of dopaminergic or glutamic acid receptor was employed to examine how amino glutaminic acid from cortex and dopamine from substantia nigra influenced two-state voltage oscillations.
It was found that 65.2% (30/46) MSNs recorded in corticostriatonigral slices displayed spontaneous and two-state voltage oscillations.92.3% (24/26) of MSNs in dorsal striatum close to cortex. And the percentage was only 30% (6/20) in ventral striatum. The amplitude of depolarized plateau potential (up state) decreased through a blockage of dopamine receptor (P < 0.05). The potential level of up state decreased through a blockage of D1 receptor (P < 0.05) and action potentials were stopped. The results of blocking D2 receptors were the increased potentials level of two states (P < 0.05). The membrane potential of MSNs showed a stable resting level in corticostriatonigral (-67 ± 3 mV, n = 10), corticostriatal (-70 ± 3 mV, n = 10), striatal (-73 ± 3 mV, n = 10) and nigrostriatal (-71 ± 3 mV, n = 10) slices. There was no significant difference (P > 0.05) .
Endogenous dopamine from substantia nigra may regulate the instantaneous integration and coding of information from cortex by tonic effect on short-term plasticity of paired and short pulses in corticostriatal synapses.
采用电生理学方法探讨内源性多巴胺（DA）对急性脑片纹状体中等棘状神经元（MSNs）的影响，阐明黑质纹状体回路对MSNs功能状态的影响。
利用纹状体与皮质或/和黑质的各种结构组合，探索出现自发双态电压振荡的条件。采用多巴胺能或谷氨酸受体阻断剂，研究来自皮质的氨基谷氨酸和来自黑质的多巴胺如何影响双态电压振荡。
在皮质-纹状体-黑质切片中记录到的MSNs中，65.2%（30/46）显示出自发双态电压振荡。靠近皮质的背侧纹状体中92.3%（24/26）的MSNs出现该现象，而腹侧纹状体中这一比例仅为30%（6/20）。阻断多巴胺受体后，去极化平台电位（上升状态）的幅度降低（P<0.05）。阻断D1受体后，上升状态的电位水平降低（P<0.05），动作电位停止。阻断D2受体的结果是两种状态的电位水平升高（P<0.05）。在皮质-纹状体-黑质（-67±3mV，n=10）、皮质-纹状体（-70±3mV，n=10）、纹状体（-73±3mV，n=10）和黑质-纹状体（-71±3mV，n=10）切片中，MSNs的膜电位显示出稳定的静息水平，差异无统计学意义（P>0.05）。
来自黑质的内源性多巴胺可能通过对皮质-纹状体突触中配对和短脉冲的短期可塑性的紧张性作用，调节来自皮质的信息的瞬时整合和编码。
