Dopamine excites nucleus accumbens neurons through the differential modulation of glutamate and GABA release
Dopamine excites nucleus accumbens neurons through the differential modulation of glutamate and GABA release
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DOI：
10.1523/jneurosci.3280-04.2004
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发表时间：
2004-09-29
影响因子：
5.3
通讯作者：
Hjelmstad, GO
中科院分区：
文献类型：
--
作者：
Hjelmstad, GO
进入伏隔核(NAC)的传入活动发生在动作电位的爆发中。然而，目前还不清楚这个核团中的突触如何对这种突发做出反应，或者这些反应是如何被多巴胺(DA)改变的。我研究了DA对大鼠NAC脑片兴奋性和抑制性反应的影响。EPSCs和IPSCs在火车上都表现出使用依赖的抑郁。虽然DA同时抑制NAC中谷氨酸和GABA的释放，但它在训练过程中对释放有不同程度的抑制作用。在整个刺激序列中，对IPSCs的抑制持续存在，而对EPSCs的抑制逐渐减弱。这种不同的调制可能是由于GABA突触从抑制状态中恢复的钙依赖变化，在那里DA通过减少钙离子进入而起作用。因此，在持续刺激的后期，DA优先抑制GABA的释放，在爆发时产生净兴奋效应，这表明了一种增强NAC竞争输入之间的对比度以及影响该结构的长期可塑性的机制。
Afferent activity into the nucleus accumbens (NAc) occurs in bursts of action potentials. However, it is unclear how synapses in this nucleus respond to such bursts, or how these responses are altered by dopamine (DA). I examined the effects of DA on excitatory and inhibitory responses to trains of stimuli in rat NAc slices. Both EPSCs and IPSCs showed use-dependent depression during trains. Although DA inhibited both glutamate and GABA release in the NAc, it differentially inhibited release during trains. The inhibition of IPSCs persisted throughout the train of stimuli, whereas the inhibition of EPSCs progressively diminished. This differential modulation may be explained by a calcium-dependent change in the recovery from depression at the GABA synapses, where DA acts by decreasing Ca2+ entry. Thus, at later stages of sustained stimulation, DA preferentially inhibits GABA release, producing a net excitatory effect during bursts suggesting a mechanism for enhancing the contrast between competing inputs into the NAc, as well as for affecting long-term plasticity in this structure.