Department of Clinical Neurophysiology, University of Göttingen, Germany.
Clin Neurophysiol. 2012 Feb;123(2):351-7. doi: 10.1016/j.clinph.2011.07.027. Epub 2011 Sep 8.
We sought to elucidate the influence of centrally active drugs on interhemispheric inhibition (IHI) between primary motor cortices in healthy humans.
We therefore studied IHI before and 2h after intake of a single oral dose of carbamazepine, dextrometorphane, lorazepam, or placebo and compared it with the well known results for short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Drugs were tested in separate sessions and in random order.
While SICI and ICF were not altered by carbamazepine, IHI was reduced at the interstimulus interval of 8 ms. Dextrometorphane tended to enhance SICI and to reduce ICF and had no effect on IHI. Lorazepam reduced ICF as expected and enhanced IHI at the long intervals of 50 and 80ms. A moderate trend for interhemispheric facilitation was inconsistently observed at the interval 2 ms and blocked by carbamazepine. In addition, carbamazepine increased the motor threshold.
We conclude that circuits mediating short interstimulus intervals of IHI are susceptible to sodium channel blockade.
The results increase our knowledge of interhemispheric transmission.
我们旨在阐明中枢活性药物对健康人体初级运动皮质间的抑制（IHI）的影响。
因此，我们在单次口服卡马西平、右美沙芬、劳拉西泮或安慰剂后 2 小时内研究了 IHI，并将其与众所周知的短间隔皮质内抑制（SICI）和皮质内易化（ICF）的结果进行了比较。药物在单独的疗程中以随机顺序进行测试。
虽然卡马西平未改变 SICI 和 ICF，但 8ms 的刺激间隔的 IHI 降低。右美沙芬倾向于增强 SICI 并降低 ICF，对 IHI 无影响。劳拉西泮如预期的那样降低了 ICF，并在 50ms 和 80ms 的长间隔增强了 IHI。在间隔 2ms 处观察到中等程度的半球间易化趋势，但被卡马西平阻断。此外，卡马西平增加了运动阈值。
我们得出结论，介导短刺激间隔 IHI 的回路易受钠通道阻断的影响。
该结果增加了我们对半球间传递的了解。
