Broicher Tilman, Kanyshkova Tatyana, Meuth Patrick, Pape Hans-Christian, Budde Thomas
Institut für Physiologie I, Westfälische Wilhelms-Universität Münster, Münster, Germany.
Mol Cell Neurosci. 2008 Nov;39(3):384-99. doi: 10.1016/j.mcn.2008.07.012. Epub 2008 Jul 29.
T-type Ca(2+) current-dependent burst firing of thalamic neurons is thought to be involved in the hyper-synchronous activity observed during absence seizures. Here we investigate the correlation between the expression of T-channel coding genes (alpha1G, -H, -I), T-type Ca(2+) current, and the T-current-dependent low threshold Ca(2+) spike in three functionally distinct thalamic nuclei (lateral geniculate nucleus; centrolateral nucleus; reticular nucleus) in a rat model of absence epilepsy, the WAG/Rij rats, and a non-epileptic control strain, the ACI rats. The lateral geniculate nucleus and centrolateral nucleus were found to primarily express alpha1G and alpha1I, while the reticular thalamic nucleus expressed alpha1H and alpha1I. Expression was higher in WAG/Rij when compared to ACI. The T-type Ca(2+) current properties matched the predictions derived from the expression pattern analysis. Current density was larger in all nuclei of WAG/Rij rats when compared to ACI and correlated with LTS size and the minimum LTS generating slope, while T-type Ca(2+) current voltage dependency correlated with the LTS onset potential.
丘脑神经元的T型Ca(2+)电流依赖性爆发式放电被认为与失神发作期间观察到的超同步活动有关。在此，我们研究了失神癫痫大鼠模型WAG/Rij大鼠以及非癫痫对照品系ACI大鼠中，三个功能不同的丘脑核团（外侧膝状体核、中央外侧核、网状核）中T通道编码基因（α1G、-H、-I）的表达、T型Ca(2+)电流以及T电流依赖性低阈值Ca(2+)尖峰之间的相关性。结果发现，外侧膝状体核和中央外侧核主要表达α1G和α1I，而丘脑网状核表达α1H和α1I。与ACI相比，WAG/Rij中的表达更高。T型Ca(2+)电流特性与从表达模式分析得出的预测相符。与ACI相比，WAG/Rij大鼠所有核团中的电流密度更大，且与低阈值尖峰大小和产生低阈值尖峰的最小斜率相关，而T型Ca(2+)电流电压依赖性与低阈值尖峰起始电位相关。
