Taspinar Numan, Hacimuftuoglu Ahmet, Butuner Selcuk, Togar Basak, Arslan Gokhan, Taghizadehghalehjoughi Ali, Okkay Ufuk, Agar Erdal, Stephens Robert, Turkez Hasan, Abd El-Aty A M
Department of Medical Pharmacology, Faculty of Medicine, Uşak University, Uşak, Turkey.
Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey.
Clin Exp Pharmacol Physiol. 2021 Dec;48(12):1662-1673. doi: 10.1111/1440-1681.13575. Epub 2021 Aug 28.
Epilepsy is a neurological disorder resulting from abnormal neuronal firing in the brain. Glutamate transporters and the glutamate-glutamine cycle play crucial roles in the development of seizures. In the present study, the correlation of epilepsy with glutamate transporters and enzymes was investigated. Herein, male Wistar rats were randomly allocated into four groups (six animals/group); 35 mg/kg pentylenetetrazole (PTZ) was used to induce a kindling model of epilepsy. Once the kindling model was established, animals were treated for 15 days with either valproic acid (VPA, 350 mg/kg) or ceftriaxone (CEF, 200 mg/kg) in addition to the control group receiving saline. After treatment, electrocorticography (ECoG) was performed to record the electrical activity of the cerebral cortex. The glutamate reuptake time (T ) was also determined in situ using an in vivo voltammetry. The expression levels of glutamate transporters and enzymes in the M1 and CA3 areas of the brain were determined using a real-time polymerase chain reaction (RT-PCR). ECoG measurements showed that the mean spike number of the PTZ + VPA and PTZ + CEF groups was significantly lower (p < 0.05) than that of the PTZ group. Compared with the PTZ group, VPA or CEF treatment decreased the glutamate reuptake time (T ). The expression levels of EAAC1, GLT-1, GLAST, glutamine synthetase (GS), and glutaminase were increased in the PTZ group. Treatment with VPA or CEF enhanced the expression levels of GLT-1, GLAST, EAAC1, and GS, whereas the glutaminase expression level was reduced. The current results suggest that VPA or CEF decreases seizure activity by increasing glutamate reuptake by upregulating GLT-1 and GLAST expression, implying a possible mechanism for treating epilepsy. Also, we have suggested a novel mechanism for the antiepileptic activity of VPA via decreasing glutaminase expression levels. To our knowledge, this is the first study to measure the glutamate reuptake time in situ during the seizure (i.e., real-time measurement).
癫痫是一种由大脑神经元异常放电引起的神经系统疾病。谷氨酸转运体和谷氨酸-谷氨酰胺循环在癫痫发作的发展过程中起着关键作用。在本研究中，对癫痫与谷氨酸转运体和酶之间的相关性进行了研究。在此，将雄性Wistar大鼠随机分为四组（每组6只动物）；使用35mg/kg的戊四氮（PTZ）诱导癫痫点燃模型。一旦点燃模型建立，除了接受生理盐水的对照组外，动物用丙戊酸（VPA，350mg/kg）或头孢曲松（CEF，200mg/kg）治疗15天。治疗后，进行皮质脑电图（ECoG）记录大脑皮质的电活动。还使用体内伏安法原位测定谷氨酸再摄取时间（T）。使用实时聚合酶链反应（RT-PCR）测定大脑M1区和CA3区谷氨酸转运体和酶的表达水平。ECoG测量显示，PTZ+VPA组和PTZ+CEF组的平均棘波数量显著低于PTZ组（p<0.05）。与PTZ组相比，VPA或CEF治疗降低了谷氨酸再摄取时间（T）。PTZ组中兴奋性氨基酸载体1（EAAC1）、谷氨酸转运体1（GLT-1）、谷氨酸天冬氨酸转运体（GLAST）、谷氨酰胺合成酶（GS）和谷氨酰胺酶的表达水平升高。VPA或CEF治疗增强了GLT-1、GLAST、EAAC1和GS的表达水平，而谷氨酰胺酶的表达水平降低。目前的结果表明，VPA或CEF通过上调GLT-1和GLAST的表达增加谷氨酸再摄取，从而降低癫痫发作活动，这意味着一种治疗癫痫的可能机制。此外，我们还提出了一种通过降低谷氨酰胺酶表达水平来解释VPA抗癫痫活性的新机制。据我们所知，这是第一项在癫痫发作期间原位测量谷氨酸再摄取时间（即实时测量）的研究。
