Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
Analyst. 2016 Jun 21;141(12):3746-55. doi: 10.1039/c6an00196c. Epub 2016 Apr 11.
The olfactory tubercle (OT), as a component of the ventral striatum, serves as an important multisensory integration center for reward-related processes in the brain. Recent studies show that dense dopaminergic innervation from the ventral tegmental area (VTA) into the OT may play an outsized role in disorders such as psychostimulant addiction and disorders of motivation, increasing recent scientific interest in this brain region. However, due to its anatomical inaccessibility, relative small size, and proximity to other dopamine-rich structures, neurochemical assessments using conventional methods cannot be readily employed. Here, we investigated dopamine (DA) regulation in the OT of urethane-anesthetized rats using in vivo fast-scan voltammetry (FSCV) coupled with carbon-fiber microelectrodes, following optogenetic stimulation of the VTA. The results were compared with DA regulation in the nucleus accumbens (NAc), a structure located adjacent to the OT and which also receives dense DA innervation from the VTA. FSCV coupled with optically evoked release allowed us to investigate the spatial distribution of DA in the OT and characterize OT DA dynamics (release and clearance) with subsecond temporal and micrometer spatial resolution for the first time. In this study, we demonstrated that DA transporters play an important role in regulating DA in the OT. However, the control of extracellular DA by uptake in the OT was less than in the NAc. The difference in DA transmission in the terminal fields of the OT and NAc may be involved in region-specific responses to drugs of abuse and contrasting roles in mediating reward-related behavior.
嗅结节（OT）作为腹侧纹状体的一个组成部分，是大脑中与奖励相关过程的重要多感觉整合中心。最近的研究表明，来自腹侧被盖区（VTA）的密集多巴胺能神经支配进入 OT 可能在精神兴奋剂成瘾和动机障碍等疾病中发挥重要作用，这增加了人们对该脑区的近期科学兴趣。然而，由于其解剖学上的不可及性、相对较小的体积以及与其他富含多巴胺的结构的接近性，使用传统方法的神经化学评估无法轻易进行。在这里，我们使用结合碳纤维微电极的活体快速扫描伏安法（FSCV），在对 VTA 进行光遗传学刺激后，研究了乌拉坦麻醉大鼠 OT 中的多巴胺（DA）调节。结果与来自 VTA 的密集 DA 支配的毗邻结构伏隔核（NAc）中的 DA 调节进行了比较。FSCV 与光诱发释放相结合，使我们能够首次以亚秒级时间和微米级空间分辨率研究 OT 中 DA 的空间分布，并对 OT DA 动力学（释放和清除）进行特征描述。在这项研究中，我们证明了 DA 转运体在调节 OT 中的 DA 中发挥着重要作用。然而，在 OT 中通过摄取来控制细胞外 DA 的作用小于在 NAc 中。OT 和 NAc 终末场中 DA 传递的差异可能涉及到对滥用药物的区域特异性反应，以及在介导与奖励相关的行为方面的对比作用。
