An inverse correlation between the apparent rate of dopamine clearance and tonic autoinhibition in subdomains of the rat striatum: a possible role of transporter-mediated dopamine efflux
An inverse correlation between the apparent rate of dopamine clearance and tonic autoinhibition in subdomains of the rat striatum: a possible role of transporter-mediated dopamine efflux
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DOI：
10.1111/j.1471-4159.2011.07183.x
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发表时间：
2011-04-01
影响因子：
4.7
通讯作者：
Michael, Adrian C.
中科院分区：
文献类型：
--
作者：
Moquin, Keith F.;Michael, Adrian C.
P>大鼠纹状体中的多巴胺能末端场被划分为多个子域，这些子域表现出电诱发多巴胺释放的独特动力学。快速纹状体区域主要以囊泡形式释放多巴胺，表现出传统的多巴胺能活性。然而，囊泡多巴胺的释放在慢域中受到强直性自身抑制，这表明多巴胺通过非囊泡途径到达自身受体。因此，这些结构域似乎使用不同的机制来调节可激活或不激活突触前自身抑制受体的基础多巴胺浓度。然而，直接检测紧张性细胞外多巴胺浓度的局部变化尚不可能。因此，本研究采用伏安法来检验多巴胺从细胞外间隙的表观清除率应该是域依赖性的假设。多巴胺清除率的表观速率等于决定细胞外多巴胺浓度的多巴胺释放和摄取速率的差异。这项研究证实，在慢纹状体区域，多巴胺清除的表观速率较慢，其中囊泡多巴胺的释放受到强直性自动抑制。这些发现支持这样的观点，即慢域中的基础浓度是通过非囊泡释放过程维持的，可能是转运蛋白介导的外排。
P>The dopaminergic terminal field in the rat striatum is compartmentalized into sub-domains that exhibit distinct dynamics of electrically evoked dopamine release. The fast striatal domains, where dopamine release is predominantly vesicular, exhibit conventional dopaminergic activity. However, vesicular dopamine release is tonically autoinhibited in the slow domains, which suggests that dopamine reaches the autoreceptors via a non-vesicular route. Hence, it appears that the domains use distinct mechanisms to regulate the basal dopamine concentration available to activate, or not, pre-synaptic autoinhibitory receptors. However, direct detection of local variations in tonic extracellular dopamine concentrations is not yet possible. So, the present study employed voltammetry to test the hypothesis that the apparent rate of dopamine clearance from the extracellular space should be domain-dependent. The apparent rate of dopamine clearance is equal to the difference in the rates of dopamine release and uptake that determine extracellular dopamine concentrations. This study confirms that the apparent rate of dopamine clearance is slower in the slow striatal domains where vesicular dopamine release is tonically autoinhibited. These findings support the view that the basal concentration in slow domains is maintained by a non-vesicular release process, possibly transporter-mediated efflux.