Probing the Role of Serotonin in Neuropathic Pain with Flexible Carbon Microelectrode Arrays

项目总结 多年来，抗抑郁药物一直是慢性疼痛的一线治疗药物。但临床疗效不佳。 选择性5-羟色胺再摄取抑制剂(SSRI‘s)在不同的不同地区一直是中等和高度可变的 条件，这需要更深入地了解5-羟色胺在调节疼痛中的作用，在解剖学和 受体特有的方式。最近感兴趣的一个领域是杏仁核。神经病理性损伤后，神经活动 杏仁核在时序化过程中发生了变化，同时也检测到了5-羟色胺的变化。 抑制杏仁基底外侧核(BLA)5-HT2C受体“允许”SSRI诱导 减轻啮齿动物的疼痛。此外，5-HT2C的基因破坏可以防止神经病理性疼痛的发展。 综上所述，这些数据支持通过5-HT2C增加5-HT信号的假设 有助于慢性疼痛的发展和维持，并最终影响 SSRI是用来治疗疼痛的。 为了验证这一假设，有必要随着时间的推移监测血中5-羟色胺的动态和神经活动 从急性期到慢性期的神经性损伤后。目前，还没有植入式传感器能够多路传输 在记录数天电生理的同时，同时检测到时相和紧张性5-羟色胺的释放。在这 方案中，我们引入了由玻璃炭制成的新型柔性多电极阵列“GC-MEAs”。 柔性和超薄聚合物衬底上的微电极位置和互连。GC-MEAS将有能力 相位型5-羟色胺(快速扫描循环伏安法)和紧张型5-羟色胺(方波伏安法)检测， 以及4周以上的活体神经活动记录。我们的GC-MEA代表了一项实质性的技术 对5-羟色胺动力学认识上的突破。首先(目标1)，我们将优化制造工艺和 材料获得最坚固的装置，具有稳定、灵敏和选择性的检测。下一步(目标2)我们将 在BLA中敏锐地和长期地验证这项技术，为期四周。最后(目标3)，我们将监测补药 备用小鼠急性期和慢性期血中5-羟色胺和5-羟色胺时相及神经活动 神经损伤(SNI)，加或不加SSRI治疗和5-HT2C抑制BLA。

PROJECT SUMMARY Antidepressants have been front-line treatments for chronic pain for years. However, clinical efficacy of selective serotonin reuptake inhibitors (SSRI’s) has been moderate and highly variable across different conditions, which calls for a deeper understanding of 5-HT’s role in modulating pain, in an anatomical and receptor-specific manner. One area of recent interest is the amygdala. After neuropathic injury, neural activity in the amygdala changes during the chronification process, while changes in 5-HT have also been detected. Inhibition of the 5-HT2C receptor in the basolateral nucleus of the amygdala (BLA) “permits” SSRI-induced reduction of pain in rodents. In addition, genetic disruption of 5-HT2C prevents neuropathic pain development. Taken together these data support the hypothesis that increases in 5-HT signaling through the 5-HT2C contribute to the development and maintenance of chronic pain and ultimately influence the ability of SSRI’s to be used to treat pain. To test this hypothesis, it is necessary to monitor 5-HT dynamics and neural activity over time in the BLA after neuropathic injury from acute through chronic phases. Currently no implantable sensor is capable of multi- channel detection of both phasic and tonic 5-HT release while recording electrophysiology over days. In this proposal, we introduce novel flexible multi-electrode arrays “GC-MEAs” that made of glassy carbon microelectrode sites and interconnects on flexible and ultrathin polymer substrate. The GC-MEAs will be capable of phasic 5-HT (with fast scan cyclic voltammetry) and tonic 5-HT (with square wave voltammetry) detections, as well as neural activity recordings in vivo over 4 weeks. Our GC-MEAs represent a substantive technological breakthrough in the understanding of 5-HT dynamics. First (Aim 1), we will optimize the fabrication process and materials to obtain the most robust device with stable, sensitive and selective detection. Next (Aim 2) we will validate this technology in the BLA acutely and chronically for four weeks. Finally (Aim 3), we will monitor tonic and phasic 5-HT as well as neural activities in the BLA of mice during acute and chronic phases of a Spared Nerve Injury (SNI), with or without SSRI treatment and 5-HT2C inhibition in BLA.