Henry T R, Votaw J R, Pennell P B, Epstein C M, Bakay R A, Faber T L, Grafton S T, Hoffman J M
Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
Neurology. 1999 Apr 12;52(6):1166-73. doi: 10.1212/wnl.52.6.1166.
To determine possible sites of therapeutic action of vagus nerve stimulation (VNS), by correlating acute VNS-induced regional cerebral blood flow (rCBF) alterations and chronic therapeutic responses.
We previously found that VNS acutely induces rCBF alterations at sites that receive vagal afferents and higher-order projections, including dorsal medulla, somatosensory cortex (contralateral to stimulation), thalamus and cerebellum bilaterally, and several limbic structures (including hippocampus and amygdala bilaterally).
VNS-induced rCBF changes were measured by subtracting resting rCBF from rCBF during VNS, using [O-15]water and PET, immediately before ongoing VNS began, in 11 partial epilepsy patients. T-statistical mapping established relative rCBF increases and decreases for each patient. Percent changes in frequency of complex partial seizures (with or without secondary generalization) during three months of VNS compared with pre-VNS baseline, and T-thresholded rCBF changes (for each of the 25 regions of previously observed significant CBF change), were rank ordered across patients. Spearman rank correlation coefficients assessed associations of seizure-frequency change and t-thresholded rCBF change.
Seizure-frequency changes ranged from 71% decrease to 12% increase during VNS. Only the right and left thalami showed significant associations of rCBF change with seizure-frequency change. Increased right and left thalamic CBF correlated with decreased seizures (p < 0.001).
Increased thalamic synaptic activities probably mediate some antiseizure effects of VNS. Future studies should examine neurotransmitter-receptor alterations in reticular and specific thalamic nuclei during VNS.
通过关联迷走神经刺激（VNS）急性诱导的局部脑血流（rCBF）改变和慢性治疗反应，确定VNS可能的治疗作用位点。
我们先前发现，VNS急性诱导接受迷走神经传入和高级投射的位点的rCBF改变，包括双侧背髓、体感皮层（刺激对侧）、丘脑和小脑，以及几个边缘结构（包括双侧海马和杏仁核）。
在11例部分性癫痫患者中，在即将开始进行VNS之前，使用[O-15]水和PET，通过从VNS期间的rCBF中减去静息rCBF来测量VNS诱导的rCBF变化。T统计映射确定了每位患者的相对rCBF增加和减少情况。将VNS三个月期间复杂部分性发作（有或无继发性全面性发作）的频率变化百分比与VNS前基线进行比较，并对25个先前观察到显著CBF变化的区域中每个区域的T阈值化rCBF变化，在患者之间进行排序。Spearman等级相关系数评估发作频率变化与T阈值化rCBF变化之间的关联。
VNS期间发作频率变化范围为降低71%至增加12%。只有右侧和左侧丘脑显示出rCBF变化与发作频率变化之间存在显著关联。右侧和左侧丘脑CBF增加与发作减少相关（p<0.001）。
丘脑突触活动增加可能介导了VNS的一些抗癫痫作用。未来的研究应检查VNS期间网状和特定丘脑核中的神经递质-受体改变。
