Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States.
Neuroscience Center, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States.
ACS Chem Neurosci. 2017 Nov 15;8(11):2512-2521. doi: 10.1021/acschemneuro.7b00266. Epub 2017 Sep 5.
Spreading depolarizations (SD) are pathophysiological phenomena that spontaneously arise in traumatized neural tissue and can promote cellular death. Most investigations of SD are performed in the cortex, a brain region that is susceptible to these depolarizing waves and accessible via a variety of monitoring techniques. Here, we describe SD responses in the cortex and the deep brain region of the nucleus accumbens (NAc) of the anesthetized rat with a minimally invasive, implantable sensor. With high temporal resolution, we characterize the time course of oxygen responses to SD in relation to the electrophysiological depolarization signal. The predominant oxygen pattern consists of four phases: (1) a small initial decrease, (2) a large increase during the SD, (3) a delayed increase, and (4) a persistent decrease from baseline after the SD. Oxygen decreases during SD were also recorded. The latter response occurred more often in the NAc than the cortex (56% vs 20% of locations, respectively), which correlates to denser cortical vascularization. We also find that SDs travel more quickly in the cortex than NAc, likely affected by regional differences in cell type populations. Finally, we investigate the previously uncharacterized effects of dopamine release during SD in the NAc with dopamine receptor blockade. Our results support an inhibitory role of the D2 receptor on SD. As such, the data presented here expands the current understanding of within- and between-region variance in responses to SD.
去极化扩散（SD）是一种在创伤性神经组织中自发出现的病理生理现象，可促进细胞死亡。大多数关于 SD 的研究都是在皮质中进行的，皮质是一个容易受到这些去极化波影响的大脑区域，可以通过各种监测技术进行监测。在这里，我们描述了麻醉大鼠皮质和伏隔核（NAc）深部脑区的 SD 反应，使用了一种微创、可植入的传感器。我们以高时间分辨率，描述了与电生理去极化信号相关的氧反应到 SD 的时间过程。主要的氧模式包括四个阶段：（1）初始小幅度下降，（2）SD 期间大幅度增加，（3）延迟增加，（4）SD 后基线持续下降。在 SD 期间也记录到了氧的减少。后者的反应在 NAc 中比皮质更常见（分别为 56%和 20%的位置），这与皮质血管密度较高有关。我们还发现，SD 在皮质中的传播速度比 NAc 快，这可能受到细胞类型群体的区域差异的影响。最后，我们研究了以前未描述的在 NAc 中多巴胺释放对 SD 的影响，并通过多巴胺受体阻断进行了研究。我们的结果支持 D2 受体对 SD 的抑制作用。因此，这里呈现的数据扩展了对 SD 反应的区域内和区域间差异的现有理解。
