摘要
目的 研究急性脑片中内源性多巴胺(DA)在纹状体中等多棘神经元(MSN)电生理活动中的作用,探讨黑质-纹状体环路联系对MSN功能状态的影响.方法 采用纹状体与皮质或黑质各种不同组合方式的矢状位脑片,观察纹状体MSN膜电位双相波动出现的条件.在皮质-纹状体-黑质脑片中,分别阻断DA受体和谷氨酸(Glu)受体,研究来自皮质的Glu和来自黑质的DA对MSN膜电位双相波动影响.结果 皮质-纹状体-黑质脑片中,65.2%的MSN(30/46)记录到自发的膜电位双相波动,在接近皮质的背侧纹状体有92.3%的MSN(24/26)表现为膜电位双相波动;而腹侧纹状体只有30%的MSN(6/20)出现膜电位的波动.阻断DA受体使去极化平台电位(up state)的幅度明显降低(P〈0.05),其中阻断DA D1受体降低up state的水平(P〈0.05),阻断动作电位的发放;而阻断D2受体使膜电位的双相状态均抬高(P〈0.05).在皮质-纹状体脑片、纹状体脑片、纹状体-黑质脑片中,MSN膜电位呈现为稳定的静息状态,各组MSN静息电位值:皮质-纹状体-黑质脑片[(-67±3)mV,n=10];皮质-纹状体脑片[(-70±3)mV,n=10];纹状体脑片[(-73±3)mV,n=10];纹状体黑质脑片[(-71±3)mV,n=10],差异无统计学意义(P〉0.05).结论 MSN膜电位的双相波动是在DA的调节下对皮质Glu能兴奋性输入的反应,是纹状体与皮质、黑质间神经环路功能完整的表现.
Objective 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. Methods 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 aminoglutaminic acid from cortex and dopamine from substantia nigra influenced two-state voltage oscillations. Results 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 ). Conclusion 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 eorticostriatal synapses.
出处
《中华医学杂志》
CAS
CSCD
北大核心
2013年第43期3470-3474,共5页
National Medical Journal of China
关键词
多巴胺
谷氨酸
纹状体
膜电位
Dopamine
Glutamic Acid
Corpus stiiatum
Membrane potentials