The Medial Entorhinal Cortex and Temporal Lobe Epilepsy

描述（由申请人提供）：颞叶癫痫（TLE）是一种破坏性的癫痫发作性疾病，现有抗癫痫药物难以控制。为了更好地了解癫痫发生的过程，并为TLE的管理开发创新的治疗方法，已经开发了动物模型，显示出这种癫痫发作障碍的特征：对中枢神经系统的初始损害，潜伏期可变，最终发展为颞叶起源的自发性癫痫发作。本提案的总体目标是确定内侧内嗅皮层（mEC）在TLE模型慢性癫痫发展中的作用。本研究将验证这样一种假设，即在TLE的kainic酸模型中，mEC浅层神经元的电路改变和兴奋性突触功能的改变至少在一定程度上导致了mEC-海马（HC）神经回路的高兴奋性和同步性。这一假设将通过使用全细胞膜片钳技术在从对照大鼠和受kainic酸诱导的TLE癫痫持续状态（SE）模型（目的2和3）的大鼠中获得的mEC-HC联合脑切片制备中进行验证，以实现以下具体目的：1)比较和对比正常动物脑切片mEC III层PYR细胞和II层STEL细胞兴奋性突触后电流（EPSCs）的动力学、短期可塑性和药理学调节。2)确定盐酸盐诱导SE后，mEC中STEL细胞在不同时间点的电响应膜性质是否有进行性变化。确定盐酸盐诱导SE后，II层STEL细胞中EPSCs的动力学、短期可塑性和药理调节是否随时间变化。3)确定KA治疗后STEL细胞间单突触连接的可能性是否增加。通过观察TLE动物模型中mEC主要神经元功能变化的发展，我们将深入了解PYR细胞退化的原因，STEL细胞过度兴奋的原因，以及这些变化对mEC- hc电路的功能影响。这些实验将为未来治疗耐药性癫痫的治疗干预措施的发展奠定基础。

DESCRIPTION (provided by applicant): Temporal lobe epilepsy (TLE) is a devastating type of seizure disorder that is difficult to control with existing antiepileptic drugs. In order to better understand the process of epileptogenesis and to develop innovative therapeutic approaches for the management of TLE, animal models have been developed that exhibit the hallmarks of this seizure disorder: an initial insult to the CNS, a variable latent period, and the eventual development of spontaneous seizures of temporal lobe origin. The overall goal of this proposal is to determine the role of the medial entorhinal cortex (mEC) in the development of chronic epilepsy in the kainic acid model of TLE. This proposal will test the hypothesis that altered circuitry and changes in excitatory synaptic function of neurons in the superficial layers of the mEC contribute, at least in part, to hyperexcitability and synchronization in the mEC-hippocampal (HC) neural circuit in the kainic acid model of TLE. This hypothesis will be tested by using the whole cell patch clamp technique in the combined mEC-HC brain slice preparation obtained from control rats and those subjected to the kainic acid-induced status epilepticus (SE) model of TLE (Aims 2 & 3) to perform the following specific aims: 1) Compare and contrast the kinetics, short-term plasticity, and pharmacological modulation of excitatory postsynaptic currents (EPSCs) in Layer III PYR cells and Layer II STEL cells of the mEC in brain slices obtained from normal animals. 2) Determine if there are progressive changes in the electroresponsive membrane properties of STEL cells in the mEC at various time points following kainate-induced SE. Determine if there are alterations in the kinetics, short-term plasticity, and pharmacological modulation of EPSCs in Layer II STEL cells as a function of time following kainate-induced SE. 3) Determine if there is an enhanced probability of monosynaptic connections between STEL cells following KA treatment. By surveying the development of functional changes in principle neurons of the mEC in an animal model of TLE, we will gain insight into why PYR cells degenerate, why STEL cells become hyperexcitable, and what the functional impact of these changes are for the mEC-HC circuit. These experiments will set the stage for the development of future therapeutic interventions for the treatment of pharmacoresistant epilepsy.