Epileptogenesis induces long-term alterations in intracellular calcium release and sequestration mechanisms in the hippocampal neuronal culture model of epilepsy
Epileptogenesis induces long-term alterations in intracellular calcium release and sequestration mechanisms in the hippocampal neuronal culture model of epilepsy
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DOI：
10.1054/ceca.2001.0236
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发表时间：
2001-10-01
期刊：
影响因子：
4
通讯作者：
DeLorenzo, RJ
中科院分区：
文献类型：
--
作者：
Pal, S;Sun, D;DeLorenzo, RJ
钙和钙依赖性过程已被假设参与癫痫的诱导。在海马神经元培养（HNC）和匹罗卡品癫痫模型中，癫痫神经元在癫痫发生后改变了钙稳态机制。为了研究引起癫痫发生后[Ca 2 +]（i）稳态过程中这些改变的机制，我们利用了产生自发复发性癫痫样放电（SRED）的体外“癫痫”的HNC模型。使用[Ca 2 +]（i）成像，开始研究以评价介导[Ca 2 +]（i）稳态中这些变化的机制。与对照神经元相比，“癫痫”神经元需要更长的时间来将谷氨酸诱导的[Ca 2 +]（i）负荷恢复到基线水平。抑制电压门控和受体门控Ca ~（2+）通道以及牵张激活Ca ~（2+）通道的Ca ~（2+）内流对谷氨酸诱导的癫痫神经元[Ca ~（2+）]（i）增加无影响。采用毒胡萝卜素，肌质/内质网钙ATP酶（SERCA）的抑制剂，它表明毒胡萝卜素抑制螯合[Ca 2 +]（i）的SERCA是显着减少在'癫痫'神经元。使用钙诱导的钙释放（CICR）细胞渗透性抑制剂的ryanodine受体（丹曲林）和IP 3受体（2-氨基-乙氧基二苯基硼酸盐，2APB）介导的CICR，我们证明，CICR显着增加的“癫痫”神经元，并确定IP 3受体介导的CICR是癫痫发生的主要释放机制改变。这些数据表明，SERCA的抑制和CICR活性的增强都有助于解释在“癫痫”神经元中观察到的钙稳态过程受损的改变。结果表明，癫痫发生后[Ca 2 +]（i）水平的持续变化可能有助于癫痫中表现出的长期可塑性变化，了解介导这些变化的基本机制可能有助于开发新的治疗方法来治疗癫痫并预防或逆转癫痫发生。(C)2001年哈考特出版社有限公司
Calcium and calcium-dependent processes have been hypothesized to be involved in the induction of epilepsy. It has been shown that epileptic neurons have altered calcium homeostatic mechanisms following epileptogenesis in the hippocampal neuronal culture (HNC) and pilocarpine models of epilepsy. To investigate the mechanisms causing these alterations in [Ca2+](i) homeostatic processes following epileptogenesis, we utilized the HNC model of in vitro 'epilepsy' which produces spontaneous recurrent epileptiform discharges (SREDs). Using [Ca2+](i) imaging, studies were initiated to evaluate the mechanisms mediating these changes in [Ca2+](i) homeostasis. 'Epileptic' neurons required much longer to restore a glutamate induced [Ca2+](i) load to baseline levels than control neurons. Inhibition of Ca2+ entry through voltage and receptor gated Ca2+ channels and stretch activated Ca2+ channels had no effect on the prolonged glutamate induced increase in [Ca2+](i) in epileptic neurons. Employing thapsigargin, an inhibitor of the sarco/endoplasmic reticulum calcium ATPase (SERCA), it was shown that thapsigargin inhibited sequestration of [Ca2+](i) by SERCA was significantly decreased in 'epileptic' neurons. Using Ca2+ induced Ca2+ release (CICR) cell permeable inhibitors for the ryanodine receptor (dantrolene) and the IP3 receptor (2-amino-ethoxydiphenylborate, 2APB) mediated CICR, we demonstrated that CICR was significantly augmented in the 'epileptic' neurons, and determined that the IP3 receptor mediated CICR was the major release mechanism altered in epileptogenesis. These data indicate that both inhibition of SERCA and augmentation of CICR activity contribute to the alterations accounting for the impaired calcium homeostatic processes observed in 'epileptic' neurons. The results suggest that persistent changes in [Ca2+](i) levels following epileptogenesis may contribute to the long-term plasticity changes manifested in epilepsy and that understanding the basic mechanisms mediating these changes may provide an insight into the development of novel therapeutic approaches to treat epilepsy and prevent or reverse epileptogenesis. (C) 2001 Harcourt Publishers Ltd.