经颅直流电刺激诱导大鼠皮质血流的极性特异性变化。
Transcranial direct current stimulation induces polarity-specific changes of cortical blood perfusion in the rat.
机构信息
Department of Neurosurgery, University Medical Center Göttingen, Germany.
出版信息
Exp Neurol. 2011 Feb;227(2):322-7. doi: 10.1016/j.expneurol.2010.12.005. Epub 2010 Dec 11.
OBJECTIVE
Transcranial direct current stimulation (tDCS) induces changes in cortical excitability and improves hand-motor function in chronic stroke. These effects depend on polarity, duration of stimulation and current intensity applied. Towards evaluating the therapeutic potential of tDCS in acute stroke, we investigated tDCS-effects on cerebral blood flow (CBF) in a tDCS rat model adapted for this purpose.
METHODS
In a randomised crossover design eight Sprague-Dawley rats received three single cathodal and anodal tDCS for 15 min every other day. At each polarity, current intensities of 25, 50 and 100 μA were applied. CBF was measured prior and after tDCS for at least 30 min with laser Doppler flowmetry (LDF).
RESULTS
At higher intensities (50 and 100 μA) anodal tDCS increased CBF up to 30 min. At 100 μA CBF was increased by about 25%, at 50 μA by about 18%. In contrast, cathodal tDCS led to a decrease of CBF, likewise depending on the current intensity applied. At 100 μA the effects were about 25% of baseline levels and persisted for at least 30 min. At 25 and 50 μA, baseline-levels were mostly re-established within 30 min.
CONCLUSIONS
tDCS modulates CBF in a polarity specific way, the extent of modulation depending on the stimulation parameters applied. Because of its polarity-specificity, we assume that CBF-alterations are causally related to tDCS-induced alterations in cortical excitability via neuro-vascular coupling. tDCS may constitute a therapeutic option in acute stroke patients or in patients at risk for vasospasm-induced ischemia after subarachnoid hemorrhage.
目的
经颅直流电刺激（tDCS）可改变皮质兴奋性，改善慢性卒中患者的手部运动功能。这些影响取决于极性、刺激持续时间和应用的电流强度。为了评估 tDCS 在急性卒中中的治疗潜力，我们在为此目的而设计的 tDCS 大鼠模型中研究了 tDCS 对脑血流（CBF）的影响。
方法
在随机交叉设计中，8 只 Sprague-Dawley 大鼠接受了 3 次单阴极和阳极 tDCS，每隔一天进行 15 分钟。在每种极性下，应用 25、50 和 100 μA 的电流强度。用激光多普勒血流仪（LDF）在 tDCS 前后至少 30 分钟测量 CBF。
结果
在较高强度（50 和 100 μA）时，阳极 tDCS 可使 CBF 增加长达 30 分钟。在 100 μA 时，CBF 增加约 25%，在 50 μA 时增加约 18%。相反，阴极 tDCS 导致 CBF 下降，同样取决于应用的电流强度。在 100 μA 时，效果约为基线水平的 25%，并持续至少 30 分钟。在 25 和 50 μA 时，基线水平大多在 30 分钟内恢复。
结论
tDCS 以极性特异性方式调节 CBF，调节程度取决于应用的刺激参数。由于其极性特异性，我们假设 CBF 变化与 tDCS 诱导的皮质兴奋性变化通过神经血管耦合有关。tDCS 可能是急性卒中患者或蛛网膜下腔出血后血管痉挛性缺血风险患者的治疗选择。
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