Neuroscience Research Australia, Randwick, NSW, Australia.
Int J Neuropsychopharmacol. 2013 Sep;16(8):1695-706. doi: 10.1017/S1461145713000084. Epub 2013 Mar 8.
Transcranial direct current stimulation is an emerging treatment for brain disorders but its mode of action is not well understood. We applied 10 min 1 mA anodal transcranial direct current stimulation (tDCS) inside the bore of a 3 T MRI scanner to the left dorsolateral prefrontal cortex of 13 healthy volunteers (aged 19-28 yr) in a blinded, sham-controlled, cross-over design. Brain bioenergetics were measured from the left temporo-frontal region using 31P magnetic resonance spectroscopy before, during and for 20 min following tDCS. Brain pH rose during tDCS and remained elevated afterwards. Phosphomonoesters were significantly decreased while inorganic phosphate (Pi) also fell. Partial-least squares discriminant analysis of the data revealed two significantly different subject groups: one where phosphocreatine (PCr), ATP and Pi fell along with a larger increase in pH and one where PCr and ATP increased along with a smaller increase in pH and a slower and more sustained decrease in Pi. Group membership was predicted by baseline pH and ATP. We interpreted the effects of tDCS as driving two biochemical processes: cellular consumption of ATP causing hydrolysis of PCr via the creatine kinase reaction driving the increase in pH; synthesis of ATP and PCr by mitochondria with concomitant drop in Pi and phosphomonoester levels.
经颅直流电刺激是一种新兴的脑部疾病治疗方法，但作用机制尚不清楚。我们采用经颅直流电刺激（tDCS），将 1 mA 强度的电流刺激施加于 13 名健康志愿者（年龄 19-28 岁）左背外侧前额叶皮层，在 3T 磁共振扫描仪的磁孔内进行 10 分钟 1 mA 强度的阳极 tDCS，实验采用盲法、假刺激对照、交叉设计。在 tDCS 前后及 20 分钟内，使用 31P 磁共振波谱技术测量左颞额区的脑生物能量。tDCS 过程中脑 pH 值升高，tDCS 后仍保持升高。磷酸单酯显著减少，同时无机磷（Pi）也下降。数据的偏最小二乘判别分析显示，存在两组具有显著差异的受试者：一组磷酸肌酸（PCr）、ATP 和 Pi 下降，同时 pH 值升高更大；另一组 PCr 和 ATP 升高，同时 pH 值升高较小，Pi 下降更慢且更持续。组别的划分由基线 pH 值和 ATP 值决定。我们将 tDCS 的影响解释为驱动两种生化过程：细胞消耗 ATP，通过肌酸激酶反应导致 PCr 水解，从而增加 pH 值；线粒体合成 ATP 和 PCr，同时伴有 Pi 和磷酸单酯水平下降。
