Austin Duncan K, Amador Lourenço M D, Li Lucia M, Little Simon J, Rothwell John C
University College London, London, UK.
Monash University, Melbourne, Australia.
Neuropsychopharmacol Rep. 2025 Mar;45(1):e12493. doi: 10.1002/npr2.12493. Epub 2024 Nov 7.
Selective serotonin reuptake inhibitors are thought to exert a clinical effect through various mechanisms, including through alteration in synaptic plasticity. Repetitive transcranial magnetic stimulation can induce temporary changes in synaptic excitability in cerebral cortex that resemble long-term potentiation and long-term depression that serve as a measure of synaptic plasticity in vivo. A version of repetitive transcranial magnetic stimulation called continuous theta burst stimulation can induce inhibition of cortical excitability that can be measured through a motor evoked potential. Previous work has suggested that this response can be modulated by administration of selective serotonin reuptake inhibitors.
Thirty-one healthy volunteers received both fluoxetine 20 mg and placebo in randomly ordered sessions, followed by spaced continuous theta burst stimulation to motor cortex. Changes in Motor Evoked Potentials were then recorded over 60 min.
The response to spaced continuous theta burst stimulation did not differ significantly between fluoxetine and placebo sessions. Spaced continuous theta burst stimulation produced a paradoxical excitatory response in an unexpected number of participants.
A single dose of fluoxetine 20 mg does not influence the response to continuous theta burst stimulation. Previous results suggesting an effect of selective serotonin reuptake inhibitors on inhibitory non-invasive brain stimulation protocols may be due to insufficiently large sample sizes.
选择性5-羟色胺再摄取抑制剂被认为通过多种机制发挥临床作用，包括改变突触可塑性。重复经颅磁刺激可诱导大脑皮质突触兴奋性的暂时变化，类似于作为体内突触可塑性指标的长时程增强和长时程抑制。一种名为连续θ波爆发刺激的重复经颅磁刺激形式可诱导皮质兴奋性抑制，这可通过运动诱发电位来测量。先前的研究表明，这种反应可通过给予选择性5-羟色胺再摄取抑制剂来调节。
31名健康志愿者在随机安排的时间段内分别接受20毫克氟西汀和安慰剂，随后对运动皮质进行间隔性连续θ波爆发刺激。然后在60分钟内记录运动诱发电位的变化。
氟西汀组和安慰剂组对间隔性连续θ波爆发刺激的反应无显著差异。在数量出乎意料的参与者中，间隔性连续θ波爆发刺激产生了反常的兴奋反应。
单次服用20毫克氟西汀不影响对连续θ波爆发刺激的反应。先前有关选择性5-羟色胺再摄取抑制剂对抑制性非侵入性脑刺激方案有影响的结果可能是由于样本量不够大。
