Abstract：
To explore the pathophysiological mechanisms of antiseizure and adverse behavioural/psychiatric effects of brivaracetam and levetiracetam, in the present study, we determined the effects of brivaracetam and levetiracetam on astroglial L-glutamate release induced by artificial high-frequency oscillation (HFO) bursts using ultra-high-performance liquid chromatography. Additionally, the effects of brivaracetam and levetiracetam on protein expressions of connexin43 (Cx43) and synaptic vesicle protein 2A (SV2A) in the plasma membrane of primary cultured rat astrocytes were determined using a capillary immunoblotting system. Acutely artificial fast-ripple HFO (500 Hz) burst stimulation use-dependently increased L-glutamate release through Cx43-containing hemichannels without affecting the expression of Cx43 or SV2A in the plasma membrane, whereas acute physiological ripple HFO (200 Hz) stimulation did not affect astroglial L-glutamate release or expression of Cx43 or SV2A. Contrarily, subchronic ripple HFO and acute pathological fast-ripple HFO (500 Hz) stimulations use-dependently increased L-glutamate release through Cx43-containing hemichannels and Cx43 expression in the plasma membrane. Subchronic fast-ripple HFO-evoked stimulation produced ectopic expression of SV2A in the plasma membrane, but subchronic ripple HFO stimulation did not generate ectopic SV2A. Subchronic administration of brivaracetam and levetiracetam concentration-dependently suppressed fast-ripple HFO-induced astroglial L-glutamate release and expression of Cx43 and SV2A in the plasma membrane. In contrast, subchronic ripple HFO-evoked stimulation induced astroglial L-glutamate release, and Cx43 expression in the plasma membrane was inhibited by subchronic levetiracetam administration, but was not affected by brivaracetam. These results suggest that brivaracetam and levetiracetam inhibit epileptogenic fast-ripple HFO-induced activated astroglial transmission associated with hemichannels. In contrast, the inhibitory effect of therapeutic-relevant concentrations of levetiracetam on physiological ripple HFO-induced astroglial responses probably contributes to the adverse behavioural/psychiatric effects of levetiracetam.
摘要：
探讨布立西坦和左乙拉西坦抗癫痫发作的病理生理机制和不良行为/精神作用。在本研究中，我们使用超高效液相色谱法测定了布立西坦和左乙拉西坦对人工高频振荡（HFO）爆发引起的星形胶质细胞L-谷氨酸释放的影响。此外,采用毛细管免疫印迹法测定了布立西坦和左乙拉西坦对原代培养的大鼠星形胶质细胞质膜中连接蛋白43（Cx43）和突触小泡蛋白2A（SV2A）表达的影响。急性人工快速波纹HFO（500Hz）爆发刺激通过含Cx43的半通道使用依赖性地增加了L-谷氨酸的释放，而不影响质膜中Cx43或SV2A的表达，而急性生理波纹HFO（200Hz）刺激不影响星形胶质细胞L-谷氨酸的释放或Cx43或SV2A的表达。相反，亚慢性波纹HFO和急性病理性快速波纹HFO（500Hz）刺激通过含Cx43的半通道和质膜中Cx43的表达依赖性地增加了L-谷氨酸的释放。亚慢性快速波纹HFO诱发刺激在质膜中产生SV2A的异位表达，但亚慢性波纹HFO刺激未产生异位SV2A。布立西坦和左乙拉西坦的亚慢性给药浓度依赖性地抑制了快速纹波HFO诱导的星形胶质细胞L-谷氨酸的释放以及质膜中Cx43和SV2A的表达。相比之下,亚慢性波纹HFO诱发刺激诱导星形胶质细胞L-谷氨酸释放，和Cx43在质膜中的表达被亚慢性左乙拉西坦给药抑制，但不受brivaracetam的影响。这些结果表明，布立拉西坦和左乙拉西坦抑制了与半通道相关的致癫痫性快速波纹HFO诱导的活化星形胶质细胞传播。相比之下,治疗相关浓度的左乙拉西坦对生理性波纹HFO诱导的星形胶质细胞反应的抑制作用可能与左乙拉西坦的不良行为/精神影响有关.
