Pierantozzi Mariangela, Marciani Maria Grazia, Palmieri Maria Giuseppina, Brusa Livia, Galati Salvatore, Caramia Maria Donatella, Bernardi Giorgio, Stanzione Paolo
IRCCS Fondazione S. Lucia Roma, via Ardeatina 306, 00173 Roma, Italy.
Brain Res. 2004 Nov 26;1028(1):1-8. doi: 10.1016/j.brainres.2004.06.009.
In this study, transcranial magnetic stimulation (TMS) of the hand primary motor area was used to test possible excitability changes induced by the administration of Vigabatrin (Gamma-Vinyl-gamma-aminobutryic acid;4-amino-hex-5-enoic acid; GVG), a selective GABAergic drug, on cortical inhibitory mechanisms in healthy subjects. In a group of 15 healthy volunteers, the level of motor cortical excitability was studied by means of paired-pulse TMS (p-TMS) protocols exploring the early (1-6 ms of interstimulus intervals, ISI) and the late cortical inhibition (20-250 ms ISI), and by evaluating the cortical silent period (CSP) duration obtained in response to single pulse stimulation of cortical motor area. In all participants TMS procedures were carried out before and after administering GVG for three consecutive days at a daily dosage of 50 mg/kg. Three months later, a third TMS recording session was repeated to investigate possible long-lasting GVG effects on cortical excitability. GVG induces relevant changes of cortical excitability consisting in an increase of late cortical inhibition in response to the long ISI p-TMS and in a prolonged duration of the CSP. No significant change in the early cortical inhibition was observed in response to the short ISI p-TMS. The analysis of peripheral motor excitability was also assessed, with no effects. The present electrophysiological data show that GVG is able to induce a significant increase of the late cortical inhibition, whereas it does not affect the early cortical inhibition. These data suggest that the great availability of synaptic GABA differently acts on the inhibitory circuitries controlled by different GABA-receptor subtypes.
在本研究中，采用经颅磁刺激（TMS）手部初级运动区，以测试选择性GABA能药物氨己烯酸（γ-乙烯基-γ-氨基丁酸；4-氨基己-5-烯酸；GVG）对健康受试者皮质抑制机制可能引起的兴奋性变化。在一组15名健康志愿者中，通过配对脉冲TMS（p-TMS）方案研究运动皮质兴奋性水平，该方案探索早期（刺激间隔1-6毫秒，ISI）和晚期皮质抑制（ISI为20-250毫秒），并评估对皮质运动区单脉冲刺激所获得的皮质静息期（CSP）持续时间。在所有参与者中，TMS程序在连续三天每天以50mg/kg的剂量给予GVG之前和之后进行。三个月后，重复第三次TMS记录 session以研究GVG对皮质兴奋性可能的长期影响。GVG引起皮质兴奋性的相关变化，表现为对长ISI p-TMS的晚期皮质抑制增加以及CSP持续时间延长。对短ISI p-TMS未观察到早期皮质抑制有显著变化。还评估了外周运动兴奋性，未发现影响。目前的电生理数据表明，GVG能够引起晚期皮质抑制的显著增加，而不影响早期皮质抑制。这些数据表明，突触GABA的大量存在对由不同GABA受体亚型控制的抑制性回路有不同作用。
